Goodwill and Intangible Assets - Components (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Schedule of Intangible Assets by Major Class [Line Items]
Goodwill, gross	$ 14,654	$ 14,653
Goodwill	14,654	14,653
Intangible assets, gross (excluding Goodwill)	331	396
Accumulated amortization	(247)	(306)
Intangible assets, net (excluding Goodwill)	84	90
Intangible assets gross including Goodwill	14,985	15,049
Total goodwill and other intangible assets, net carrying value	14,738	14,743
Commercial MSRs, gross	562	542
Commercial MSR, accumulated amortization	(183)	(175)
Total commercial MSRs	379	367
PCCR intangibles
Schedule of Intangible Assets by Major Class [Line Items]
Intangible assets, gross (excluding Goodwill)	147	148
Accumulated amortization	(139)	(138)
Intangible assets, net (excluding Goodwill)	8	10
Other intangible assets
Schedule of Intangible Assets by Major Class [Line Items]
Intangible assets, gross (excluding Goodwill)	184	248
Accumulated amortization	(108)	(168)
Intangible assets, net (excluding Goodwill)	$ 76	$ 80