Variable Interest Entities - Income Statement Effect (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Non-Interest Income
Amortization of tax credit investments under equity method, net of tax benefit	$ 1	$ 1	$ 1
Provision for income taxes:
Amortization of LIHTC investments under proportional method	13	11	8
Low-income housing tax credits	(15)	(12)	(9)
Other tax benefits related to tax credit investments	(2)	(2)	(2)
Total impact on provision for income taxes	$ (4)	$ (3)	$ (3)