Variable Interest Entities and Securitizations - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Variable Interest Entity [Line Items]
Amortization method qualified affordable housing investments, amortization	$ 477	$ 428
Affordable housing tax credits	560	$ 47
Amortization method qualified affordable housing investments	4,700		$ 4,500
Qualified affordable housing investments, commitment	1,700		1,500
Carrying Amount of Assets	425,377		421,602
VIE, reporting entity involvement, maximum loss exposure	5,186		5,038
Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	5,186		5,038
Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	24,450		26,619
Affordable housing entities
Variable Interest Entity [Line Items]
VIE, reporting entity involvement, maximum loss exposure	4,786		4,602
Affordable housing entities | Unconsolidated
Variable Interest Entity [Line Items]
Total assets of the unconsolidated VIE investment funds	11,900		11,000
Carrying Amount of Assets	4,786		4,602
Affordable housing entities | Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	264		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	2,073		1,951
Other
Variable Interest Entity [Line Items]
VIE, reporting entity involvement, maximum loss exposure	400		436
Other | Unconsolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	400		436
Other | Consolidated
Variable Interest Entity [Line Items]
Carrying Amount of Assets	$ 0		$ 0