Variable Interest Entities - Assets and Liabilities Related to Non-consolidated VIEs and Maximum Exposure to Losses (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Variable Interest Entity
Assets	$ 206,899	$ 204,680
Liabilities	184,304	181,569
CDC investments | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity
Assets	1,546	1,546
Liabilities	435	478
Maximum Exposure	1,546	1,546
Private equity investments | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity
Assets	104	117
Liabilities	0	0
Maximum Exposure	198	200
Loans provided to VIEs | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity
Assets	2,530	2,420
Liabilities	0	0
Maximum Exposure	3,923	3,649
Lease pool entities | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity
Assets	74	73
Liabilities	0	0
Maximum Exposure	$ 74	$ 73