Goodwill and Mortgage Servicing Rights - Goodwill Changes During Period (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Goodwill [Roll Forward]
Balance at beginning of period	$ 50,315,000,000	$ 49,248,000,000	$ 49,248,000,000
Changes during the period from:
Other	(17,000,000)	(5,000,000)
Balance at end of period	50,298,000,000	$ 49,243,000,000	50,315,000,000
Goodwill impairment	$ 0		$ 0