Mortgage Servicing Rights - Changes in Fair Value of Capitalized MSRs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at beginning of period	$ 3,305	$ 3,326	$ 3,369	$ 3,377
Rights purchased	0	0	0	1
Rights capitalized	71	72	194	191
Rights sold	1	1	2	(188)
Changes in fair value of MSRs
Due to fluctuations in market interest rates	(3)	(121)	(43)	27
Due to revised assumptions or models	13	3	23	44
Other changes in fair value	(98)	(94)	(256)	(265)
Balance at end of period	$ 3,289	$ 3,187	$ 3,289	$ 3,187