v3.25.4
Average Annual Total Returns - American Century International Bond Fund
 12 Months Ended 60 Months Ended 98 Months Ended 101 Months Ended 120 Months Ended
Mar. 01, 2026
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
JP Morgan EMBI Global Diversified Index            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] JP Morgan EMBI Global Diversified Index(reflects no deduction for fees, expenses or taxes)          
Average Annual Return, Percent   14.30% 1.78%     4.40%
Bloomberg Global Aggregate Bond Index (USD, hedged)            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] Bloomberg Global Aggregate Bond Index (USD, hedged)(reflects no deduction for fees, expenses or taxes)          
Average Annual Return, Percent   4.86% 0.34%     2.39%
EMERGING MARKETS DEBT FUND, INVESTOR CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] Investor Class Return Before Taxes          
Average Annual Return, Percent   14.90% 1.79%     4.09%
Performance Inception Date Jul. 29, 2014          
EMERGING MARKETS DEBT FUND, INVESTOR CLASS | After Taxes on Distributions            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] Return After Taxes on Distributions          
Average Annual Return, Percent   12.37% (0.06%)     2.33%
Performance Inception Date Jul. 29, 2014          
EMERGING MARKETS DEBT FUND, INVESTOR CLASS | After Taxes on Distributions and Sales            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] Return After Taxes on Distributions and Sale of Fund Shares          
Average Annual Return, Percent   8.76% 0.53%     2.36%
Performance Inception Date Jul. 29, 2014          
EMERGING MARKETS DEBT FUND, I CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] [1] I Class1 Return Before Taxes          
Average Annual Return, Percent [1]   15.13% 1.91%     4.20%
Performance Inception Date [1] Apr. 10, 2017          
EMERGING MARKETS DEBT FUND, Y CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] [1] Y Class1 Return Before Taxes          
Average Annual Return, Percent [1]   15.13% 1.99%     4.28%
Performance Inception Date [1] Apr. 10, 2017          
EMERGING MARKETS DEBT FUND, A CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] A Class Return Before Taxes          
Average Annual Return, Percent   9.47% 0.61%     3.34%
Performance Inception Date Jul. 29, 2014          
EMERGING MARKETS DEBT FUND, C CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] [2] C Class2 Return Before Taxes          
Average Annual Return, Percent [2]   13.81% 0.80%     3.20%
Performance Inception Date [2] Jul. 29, 2014          
EMERGING MARKETS DEBT FUND, R CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] R Class Return Before Taxes          
Average Annual Return, Percent   14.48% 1.28%     3.57%
Performance Inception Date Jul. 29, 2014          
EMERGING MARKETS DEBT FUND, R5 CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] R5 Class Return Before Taxes          
Average Annual Return, Percent   15.13% 1.99%     4.29%
Performance Inception Date Jul. 29, 2014          
EMERGING MARKETS DEBT FUND, R6 CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] R6 Class Return Before Taxes          
Average Annual Return, Percent   14.95% 2.00%     4.32%
Performance Inception Date Jul. 29, 2014          
EMERGING MARKETS DEBT FUND, G CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] G Class Return Before Taxes          
Average Annual Return, Percent   15.94% 2.75% 4.05%    
Performance Inception Date Nov. 14, 2017          
GLOBAL BOND FUND, INVESTOR CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] Investor Class Return Before Taxes          
Average Annual Return, Percent   4.86% (0.42%)     1.79%
Performance Inception Date Jan. 31, 2012          
GLOBAL BOND FUND, INVESTOR CLASS | After Taxes on Distributions            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] Return After Taxes on Distributions          
Average Annual Return, Percent   2.91% (1.84%)     0.58%
Performance Inception Date Jan. 31, 2012          
GLOBAL BOND FUND, INVESTOR CLASS | After Taxes on Distributions and Sales            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] Return After Taxes on Distributions and Sale of Fund Shares          
Average Annual Return, Percent   2.86% (0.92%)     0.85%
Performance Inception Date Jan. 31, 2012          
GLOBAL BOND FUND, I CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] [3] I Class1 Return Before Taxes          
Average Annual Return, Percent [3]   4.94% (0.32%)     1.90%
Performance Inception Date [3] Apr. 10, 2017          
GLOBAL BOND FUND, Y CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] [3] Y Class1 Return Before Taxes          
Average Annual Return, Percent [3]   5.04% (0.22%)     2.00%
Performance Inception Date [3] Apr. 10, 2017          
GLOBAL BOND FUND, A CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] A Class Return Before Taxes          
Average Annual Return, Percent   (0.08%) (1.57%)     1.07%
Performance Inception Date Jan. 31, 2012          
GLOBAL BOND FUND, C CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] [4] C Class2 Return Before Taxes          
Average Annual Return, Percent [4]   3.80% (1.41%)     0.92%
Performance Inception Date [4] Jan. 31, 2012          
GLOBAL BOND FUND, R CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] R Class Return Before Taxes          
Average Annual Return, Percent   4.40% (0.91%)     1.28%
Performance Inception Date Jan. 31, 2012          
GLOBAL BOND FUND, R5 CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] R5 Class Return Before Taxes          
Average Annual Return, Percent   5.06% (0.22%)     1.99%
Performance Inception Date Jan. 31, 2012          
GLOBAL BOND FUND, R6 CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] R6 Class Return Before Taxes          
Average Annual Return, Percent   5.11% (0.17%)     2.04%
Performance Inception Date Jul. 26, 2013          
GLOBAL BOND FUND, G CLASS            
Prospectus [Line Items]            
Average Annual Return, Label [Optional Text] G Class Return Before Taxes          
Average Annual Return, Percent   5.70% 0.38%   2.17%  
Performance Inception Date Jul. 28, 2017          
[1] Historical performance for the I and Y Classes prior to their inception is based on the performance of R5 Class shares. I and Y Class performance has been adjusted to reflect differences in expenses between classes, if applicable. Since inception performance for the I and Y Classes is based on the R5 Class inception date.
[2] C Class shares automatically convert to A Class shares after approximately eight years. All returns for periods greater than eight years reflect this conversion.
[3] Historical performance for the I and Y Classes prior to their inception is based on the performance of R5 Class shares. I and Y Class performance have been adjusted to reflect differences in expenses between classes, if applicable. Since inception performance for the I and Y Classes is based on the R5 Class inception date.
[4] C Class shares automatically convert to A Class shares after approximately eight years. All returns for periods greater than eight years reflect this conversion.