Variable Interest Entities - Variable Interests Held by Us and Our Maximum Exposure to Loss Rising From Our Involvements in Those VIEs (Details) - USD ($) $ in Millions		Sep. 30, 2020		Dec. 31, 2019		Sep. 30, 2019
Variable Interest Entity [Line Items]
Assets		$ 200,946	[1]	$ 175,375	[1]	$ 184,760
Liabilities	[1]	182,606		157,119
Variable Interest Entity, Not Primary Beneficiary, Structured Note Vehicles [Member]
Variable Interest Entity [Line Items]
Total Assets Held by Unconsolidated VIEs				1,524
Assets				510
Liabilities				9
Maximum Exposure to Loss				1,515
Variable Interest Entity, Not Primary Beneficiary, Limited Partnership Investments [Member]
Variable Interest Entity [Line Items]
Total Assets Held by Unconsolidated VIEs		2,654		2,160
Assets		594		561
Liabilities		285		300
Maximum Exposure to Loss		$ 594		562
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Total Assets Held by Unconsolidated VIEs				3,684
Assets				1,071
Liabilities				309
Maximum Exposure to Loss				$ 2,077

[1] Assets