Goodwill, Mortgage Servicing Rights, and Other Intangible Assets - Goodwill Changes During Period (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Goodwill [Roll Forward]
Balance at beginning of period	$ 52,634,000,000	$ 51,662,000,000
Changes during the period from:
Business combinations	34,000,000	451,000,000
Other	(32,000,000)	31,000,000
Balance at end of period	52,636,000,000	52,144,000,000
Business Acquisition [Line Items]
Goodwill impairment	$ 0	$ 0
CIFM
Business Acquisition [Line Items]
Percentage interest acquired		51.00%