Variable Interest Entities - Assets and Liabilities Related to Non-consolidated VIEs and Maximum Exposure to Losses (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Variable Interest Entity
Assets	$ 204,680	$ 169,369
Liabilities	181,569	148,166
CDC investments | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity
Assets	1,546	1,435
Liabilities	478	428
Maximum Exposure	1,546	1,435
Private equity investments | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity
Assets	117	89
Liabilities	0	0
Maximum Exposure	200	164
Loans provided to VIEs | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity
Assets	2,420	2,715
Liabilities	0	0
Maximum Exposure	3,649	4,083
Lease pool entities | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity
Assets	73	74
Liabilities	0	0
Maximum Exposure	$ 73	$ 74