Goodwill and Mortgage Servicing Rights - Goodwill Changes During Period (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Goodwill [Roll Forward]
Balance at beginning of period	$ 51,662,000,000	$ 50,315,000,000	$ 50,315,000,000
Changes during the period from:
Business combinations	451,000,000	0
Other	31,000,000	(17,000,000)
Balance at end of period	52,144,000,000	$ 50,298,000,000	51,662,000,000
Goodwill impairment	$ 0		$ 0
CIFM
Business Acquisition [Line Items]
Percentage interest acquired	51.00%