Goodwill, Mortgage Servicing Rights, and Other Intangible Assets - Goodwill Changes During Period (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Mar. 31, 2023
Goodwill [Roll Forward]
Balance at beginning of period	$ 52,636,000,000	$ 52,144,000,000	$ 52,634,000,000	$ 51,662,000,000
Changes during the period from:
Business combinations	(5,000,000)
Business combinations		236,000,000	29,000,000	687,000,000
Other	(11,000,000)	0	(43,000,000)	31,000,000
Balance at end of period	$ 52,620,000,000	$ 52,380,000,000	52,620,000,000	52,380,000,000
Business Acquisition [Line Items]
Goodwill impairment			$ 0	$ 0
CIFM
Business Acquisition [Line Items]
Percentage interest acquired					51.00%