Variable Interest Entities and Securitizations - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Variable Interest Entity [Line Items]
Amortization method qualified affordable housing investments, amortization	$ 156	$ 139
Affordable housing tax credits	258	$ 155
Amortization method qualified affordable housing investments	4,600		$ 4,500
Qualified affordable housing investments, commitment	1,500		1,500
Carrying Amount of Assets	425,175		421,602
VIE, reporting entity involvement, maximum loss exposure	5,087		5,038
Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	5,087		5,038
Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	26,463		26,619
Affordable housing entities
Variable Interest Entity [Line Items]
VIE, reporting entity involvement, maximum loss exposure	4,676		4,602
Affordable housing entities | Unconsolidated
Variable Interest Entity [Line Items]
Total assets of the unconsolidated VIE investment funds	11,000		11,000
Carrying Amount of Assets	4,676		4,602
Affordable housing entities | Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	251		242
Entities that provide capital to low-income and rural communities
Variable Interest Entity [Line Items]
VIE, reporting entity involvement, maximum loss exposure	0		0
Entities that provide capital to low-income and rural communities | Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	0		0
Entities that provide capital to low-income and rural communities | Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	1,999		1,951
Other
Variable Interest Entity [Line Items]
VIE, reporting entity involvement, maximum loss exposure	411		436
Other | Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	411		436
Other | Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	$ 0		$ 0