Variable Interest Entities - Assets and Liabilities Related to Non-consolidated VIEs and Maximum Exposure to Losses (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Variable Interest Entity
Assets	$ 201,996	$ 169,369
Liabilities	179,045	148,166
Variable Interest Entity, Not Primary Beneficiary | CDC investments
Variable Interest Entity
Assets	1,473	1,435
Liabilities	436	428
Maximum Exposure	1,473	1,435
Variable Interest Entity, Not Primary Beneficiary | Private equity investments
Variable Interest Entity
Assets	96	89
Liabilities	0	0
Maximum Exposure	182	164
Variable Interest Entity, Not Primary Beneficiary | Loans provided to VIEs
Variable Interest Entity
Assets	2,515	2,715
Liabilities	0	0
Maximum Exposure	3,781	4,083
Variable Interest Entity, Not Primary Beneficiary | Lease pool entities
Variable Interest Entity
Assets	75	74
Liabilities	0	0
Maximum Exposure	$ 75	$ 74