Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - Nonrecurring - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	$ 401	$ 388
Total (Losses) Gains	(255)	(186)
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	3	0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	398	388
OREO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	2	18
Total (Losses) Gains	(2)	(8)
OREO | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	0	0
OREO | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	0	0
OREO | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	2	18
Bank premises and equipment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	7	15
Total (Losses) Gains	(1)	(2)
Bank premises and equipment | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	0	0
Bank premises and equipment | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	0	0
Bank premises and equipment | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	7	15
Operating lease equipment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value		2
Total (Losses) Gains		0
Operating lease equipment | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value		0
Operating lease equipment | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value		0
Operating lease equipment | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value		2
Private equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	3	0
Total (Losses) Gains	11	(2)
Private equity investments | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	0	0
Private equity investments | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	3	0
Private equity investments | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	0	0
Commercial | Commercial loans held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	6	1
Total (Losses) Gains	(1)	0
Commercial | Commercial loans held for sale | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	0	0
Commercial | Commercial loans held for sale | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	0	0
Commercial | Commercial loans held for sale | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	6	1
Commercial | Commercial loans and leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	168	163
Total (Losses) Gains	(245)	(162)
Commercial | Commercial loans and leases | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	0	0
Commercial | Commercial loans and leases | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	0	0
Commercial | Commercial loans and leases | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	168	163
Consumer | Consumer and residential mortgage loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	215	189
Total (Losses) Gains	(17)	(12)
Consumer | Consumer and residential mortgage loans | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	0	0
Consumer | Consumer and residential mortgage loans | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	0	0
Consumer | Consumer and residential mortgage loans | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	$ 215	$ 189