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	Dec. 31, 2016	Dec. 31, 2015
Variable Interest Entity [Line Items]
Variable Interest Held Classified as Assets	$ 3,668	$ 4,247
Variable Interests Held Classified as Liabilities	234	129
Total Assets in Unconsolidated VIEs	8,420	22,625
Maximum Exposure to Loss	6,676	10,560
Asset-backed commercial paper conduits [Member]
Variable Interest Entity [Line Items]
Variable Interest Held Classified as Assets		58
Variable Interests Held Classified as Liabilities		0
Total Assets in Unconsolidated VIEs		15,183
Maximum Exposure to Loss		3,362
Structured note vehicles [Member]
Variable Interest Entity [Line Items]
Variable Interest Held Classified as Assets	2,888	2,870
Variable Interests Held Classified as Liabilities	7	8
Total Assets in Unconsolidated VIEs	5,908	5,888
Maximum Exposure to Loss	5,896	5,879
Limited partnership investments [Member]
Variable Interest Entity [Line Items]
Variable Interest Held Classified as Assets	427	138
Variable Interests Held Classified as Liabilities	227	121
Total Assets in Unconsolidated VIEs	1,853	302
Maximum Exposure to Loss	427	138
Refinancing SPE [Member]
Variable Interest Entity [Line Items]
Variable Interest Held Classified as Assets	353	1,181	[1]
Variable Interests Held Classified as Liabilities	0	0	[1]
Total Assets in Unconsolidated VIEs	659	1,252	[1]
Maximum Exposure to Loss	$ 353	$ 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.