Mortgage Servicing Assets - Schedule of Changes in Carrying Amount of Mortgage Servicing Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Commercial Mortgage Backed Securities
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Balance at beginning of period	$ 631	$ 634	$ 638	$ 653
Servicing retained from loan sales	9	17	27	26
Purchases	4	6	10	10
Amortization	(32)	(30)	(63)	(62)
Temporary (impairments) recoveries	0	0	0	0
Balance at end of period	612	627	612	627
Fair value at end of period	866	893	866	893
Agency residential mortgage-backed securities
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Balance at beginning of period	108	105	108	106
Servicing retained from loan sales	3	3	5	4
Purchases	0	0	0	0
Amortization	(3)	(2)	(5)	(4)
Temporary (impairments) recoveries	1	0	1	0
Balance at end of period	109	106	109	106
Fair value at end of period	$ 133	$ 130	$ 133	$ 130