Fair Values - Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - Nonrecurring - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Assets at fair value
Loans	$ 2,901		$ 5,611
Other assets—Other investments	7		8
Other assets—ROU assets	4		16
Total	2,912		5,635
Liabilities at fair value
Other liabilities and accrued expenses—Lending commitments	287		243
Total	287		243
Assets
Fair Value Adjustment Disclosure
Gains (losses) from fair value remeasurements	(48)	$ (76)
Loans
Fair Value Adjustment Disclosure
Gains (losses) from fair value remeasurements	(43)	(13)
Goodwill
Fair Value Adjustment Disclosure
Gains (losses) from fair value remeasurements	0	(8)
Intangibles
Fair Value Adjustment Disclosure
Gains (losses) from fair value remeasurements	0	(2)
Other assets—Other investments
Fair Value Adjustment Disclosure
Gains (losses) from fair value remeasurements	(2)	(51)
Other assets—Premises, equipment and software
Fair Value Adjustment Disclosure
Gains (losses) from fair value remeasurements	(1)	(2)
Other assets—ROU assets
Fair Value Adjustment Disclosure
Gains (losses) from fair value remeasurements	(2)	0
Liabilities
Fair Value Adjustment Disclosure
Gains (losses) from fair value remeasurements	(49)	4
Other liabilities and accrued expenses—Lending commitments
Fair Value Adjustment Disclosure
Gains (losses) from fair value remeasurements	(49)	$ 4
Level 2
Assets at fair value
Loans	1,531		4,035
Other assets—Other investments	0		0
Other assets—ROU assets	4		16
Total	1,535		4,051
Liabilities at fair value
Other liabilities and accrued expenses—Lending commitments	201		173
Total	201		173
Level 3
Assets at fair value
Loans	1,370		1,576
Other assets—Other investments	7		8
Other assets—ROU assets	0		0
Total	1,377		1,584
Liabilities at fair value
Other liabilities and accrued expenses—Lending commitments	86		70
Total	$ 86		$ 70