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, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Variable Interest Entity [Line Items]
Variable Interests Held Classified as Assets	$ 2,865	$ 2,689
Variable Interests Held Classified as Liabilities	9	55
Total Assets in Unconsolidated VIEs	19,513	23,234
Maximum Exposure to Loss	8,233	8,448
Asset-backed commercial paper conduits [Member]
Variable Interest Entity [Line Items]
Variable Interests Held Classified as Assets	46	417
Variable Interests Held Classified as Liabilities	0	0
Total Assets in Unconsolidated VIEs	13,423	17,044
Maximum Exposure to Loss	2,303	2,560
Structured note vehicles [Member]
Variable Interest Entity [Line Items]
Variable Interests Held Classified as Assets	2,819	2,272
Variable Interests Held Classified as Liabilities	9	55
Total Assets in Unconsolidated VIEs	6,090	6,190
Maximum Exposure to Loss	$ 5,930	$ 5,888