Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - Nonrecurring - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	$ 409	$ 864
Total (Losses) Gains	(23)	(272)
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	1	35
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	408	829
OREO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	7	20
Total (Losses) Gains	(6)	(7)
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	7	20
Bank premises and equipment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	11	26
Total (Losses) Gains	(6)	(30)
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	11	26
Operating lease equipment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	13	35
Total (Losses) Gains	(21)	(6)
Operating lease equipment | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	0	0
Operating lease equipment | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	0	0
Operating lease equipment | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	13	35
Private equity investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	15	96
Total (Losses) Gains	38	18
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	1	27
Private equity investments | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	14	69
Commercial | Commercial loans held for sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	2	24
Total (Losses) Gains	2	(5)
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	8
Commercial | Commercial loans held for sale | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	2	16
Commercial | Commercial loans and leases
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	236	504
Total (Losses) Gains	(29)	(243)
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	236	504
Consumer | Consumer and residential mortgage loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets, fair value	125	159
Total (Losses) Gains	(1)	1
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	$ 125	$ 159