Fair value by balance sheet grouping table (Tables)
3 Months Ended
Mar. 31, 2024
Fair Value Disclosures [Abstract]  
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments
The carrying amount and fair value of our total debt is as follows:
March 31, 2024December 31, 2023
Millions of dollarsLevel 1Level 2Total fair valueCarrying valueLevel 1Level 2Total fair valueCarrying value
Total debt$7,294 $361 $7,655 $7,637 $7,419 $378 $7,797 $7,636