Derivative and Hedging Activities - Schedule of Notional Amount and Fair Value of Derivative Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Derivatives designated as hedging instruments: \| Interest rate swaps \| Fair value hedging
Assets
Notional Amount	$ 3,993	$ 0
Derivatives designated as hedging instruments: \| Interest rate swaps \| Other Assets \| Fair value hedging
Assets
Fair Value	0	0
Derivatives designated as hedging instruments: \| Interest rate swaps \| Other Liabilities \| Fair value hedging
Assets
Fair Value	0	0
Derivatives not designated as hedging instruments: \| Interest rate swaps
Assets
Notional Amount	3,926	3,323
Derivatives not designated as hedging instruments: \| Interest rate swaps \| Other Assets
Assets
Fair Value	19	15
Derivatives not designated as hedging instruments: \| Interest rate swaps \| Other Liabilities
Assets
Fair Value	21	30
Derivatives not designated as hedging instruments: \| Rate lock commitments
Assets
Notional Amount	241	563
Derivatives not designated as hedging instruments: \| Rate lock commitments \| Other Assets
Assets
Fair Value	4	3
Derivatives not designated as hedging instruments: \| Rate lock commitments \| Other Liabilities
Assets
Fair Value	1	3
Derivatives not designated as hedging instruments: \| Mortgage-backed securities forwards
Assets
Notional Amount	203	344
Derivatives not designated as hedging instruments: \| Mortgage-backed securities forwards \| Other Assets
Assets
Fair Value	0	7
Derivatives not designated as hedging instruments: \| Mortgage-backed securities forwards \| Other Liabilities
Assets
Fair Value	1	2
Derivatives not designated as hedging instruments: \| Interest rate caps
Assets
Notional Amount	2,000	0
Derivatives not designated as hedging instruments: \| Interest rate caps \| Other Assets
Assets
Fair Value	3	0
Derivatives not designated as hedging instruments: \| Interest rate caps \| Other Liabilities
Assets
Fair Value	$ 0	$ 0