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	Mar. 31, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Variable Interest Held Classified as Assets	$ 4,473	$ 4,247
Variable Interests Held Classified as Liabilities	160	129
Total Assets in Unconsolidated VIEs	22,752	22,625
Maximum Exposure to Loss	10,337	10,560
Asset-backed commercial paper conduits [Member]
Variable Interest Entity [Line Items]
Variable Interest Held Classified as Assets	309	58
Variable Interests Held Classified as Liabilities	0	0
Total Assets in Unconsolidated VIEs	14,958	15,183
Maximum Exposure to Loss	3,163	3,362
Structured note vehicles [Member]
Variable Interest Entity [Line Items]
Variable Interest Held Classified as Assets	2,875	2,870
Variable Interests Held Classified as Liabilities	17	8
Total Assets in Unconsolidated VIEs	5,903	5,888
Maximum Exposure to Loss	5,885	5,879
Limited partnership investments [Member]
Variable Interest Entity [Line Items]
Variable Interest Held Classified as Assets	208	138
Variable Interests Held Classified as Liabilities	143	121
Total Assets in Unconsolidated VIEs	639	302
Maximum Exposure to Loss	208	138
Refinancing SPE [Member]
Variable Interest Entity [Line Items]
Variable Interest Held Classified as Assets	1,081	1,181	[1]
Variable Interests Held Classified as Liabilities	0	0	[1]
Total Assets in Unconsolidated VIEs	1,252	1,252	[1]
Maximum Exposure to Loss	$ 1,081	$ 1,181	[1]

[1] During 2016, we revised the above table to include a refinancing SPE which was an unconsolidated VIE at December 31, 2015 as discussed further below. This revision did not have any impact on our financial position or results of operations.