Securitizations and Variable Interest Entities (Activity in Affordable Housing Program Obligation) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Securitizations And Variable Interest Entities [Abstract]
Affordable housing tax credits and other tax benefits	$ 144,000,000	$ 109,000,000	$ 86,000,000
Tax credit amortization expense recognized as a component of income tax expense	118,000,000	90,000,000	72,000,000
Affordable housing impairment	$ 0	$ 0	$ 0