Investment Securities (Investments, by type and length in continuous loss position) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Available-for-sale Securities Estimated Fair Value And Gross Unrealized Losses [Abstract]
OTTI Previously Recognized Through OCI On Securities Held, Gross Unrealized Losses	$ (99)
Marketable securities OTTI amounts	798	193	467
Cumulative impairments recognized in earnings associated with debt securities		588	726	500
Marketable securities OTTI recorded in AOCI	31	52	80
Marketable Securities, Realized Loss, Other than Temporary Impairments, Amount	767	141	387
Incremental Charges On Previously Impaired Investment Securities	336	40	230
Residential Subprime Exposure	378	471
Residential Subprime Exposure Insured By Monolines	285	219
Other Than Temporary Impairment Related To Equity Securities	15	39	81
Other Than Temporary First Time Impairments Of Investment Securities Recognized In Earnings	389	27	58
Other Than Temporary Impairment Related To Securities Subsequently Sold	120	219	62
Domestic Corporate Debt Securities [Member]
Available-for-sale Securities Estimated Fair Value And Gross Unrealized Losses [Abstract]
Estimated fair value, less than 12 months	2,170	434
Gross unrealized losses, less than 12 months	(122)	(7)
Estimated fair value, 12 months or more	598	813
Gross unrealized losses, 12 months or more	(95)	(295)
US States and Political Subdivisions Debt Securities [Member]
Available-for-sale Securities Estimated Fair Value And Gross Unrealized Losses [Abstract]
Estimated fair value, less than 12 months	1,076	146
Gross unrealized losses, less than 12 months	(82)	(2)
Estimated fair value, 12 months or more	367	326
Gross unrealized losses, 12 months or more	(109)	(111)
Residential Mortgage Backed Securities [Member]
Available-for-sale Securities Estimated Fair Value And Gross Unrealized Losses [Abstract]
Estimated fair value, less than 12 months	232	98
Gross unrealized losses, less than 12 months	(11)	(1)
Estimated fair value, 12 months or more	430	691
Gross unrealized losses, 12 months or more	(37)	(118)
Commercial Mortgage Backed Securities [Member]
Available-for-sale Securities Estimated Fair Value And Gross Unrealized Losses [Abstract]
Estimated fair value, less than 12 months	396	37
Gross unrealized losses, less than 12 months	(24)	0
Estimated fair value, 12 months or more	780	979
Gross unrealized losses, 12 months or more	(58)	(95)
Asset-backed Securities [Member]
Available-for-sale Securities Estimated Fair Value And Gross Unrealized Losses [Abstract]
Estimated fair value, less than 12 months	112	18
Gross unrealized losses, less than 12 months	(2)	(1)
Estimated fair value, 12 months or more	359	658
Gross unrealized losses, 12 months or more	(44)	(76)
Foreign Corporate Debt Securities [Member]
Available-for-sale Securities Estimated Fair Value And Gross Unrealized Losses [Abstract]
Estimated fair value, less than 12 months	108	167
Gross unrealized losses, less than 12 months	(4)	(8)
Estimated fair value, 12 months or more	454	602
Gross unrealized losses, 12 months or more	(83)	(118)
Foreign Government Debt Securities [Member]
Available-for-sale Securities Estimated Fair Value And Gross Unrealized Losses [Abstract]
Estimated fair value, less than 12 months	1,479	201
Gross unrealized losses, less than 12 months	(6)	(1)
Estimated fair value, 12 months or more	42	37
Gross unrealized losses, 12 months or more	(1)	(2)
US Treasury and Government [Member]
Available-for-sale Securities Estimated Fair Value And Gross Unrealized Losses [Abstract]
Estimated fair value, less than 12 months	229	0
Gross unrealized losses, less than 12 months	(27)	0
Estimated fair value, 12 months or more	254	0
Gross unrealized losses, 12 months or more	0	0
Retained Interest [Member]
Available-for-sale Securities Estimated Fair Value And Gross Unrealized Losses [Abstract]
Estimated fair value, less than 12 months	2	3
Gross unrealized losses, less than 12 months	0	0
Estimated fair value, 12 months or more	0	0
Gross unrealized losses, 12 months or more	0	0
Equity Securities [Member]
Available-for-sale Securities Estimated Fair Value And Gross Unrealized Losses [Abstract]
Estimated fair value, less than 12 months	253	26
Gross unrealized losses, less than 12 months	(44)	(3)
Estimated fair value, 12 months or more	0	0
Gross unrealized losses, 12 months or more	0	0
Total [Member]
Available-for-sale Securities Estimated Fair Value And Gross Unrealized Losses [Abstract]
Estimated fair value, less than 12 months	6,057	1,130
Gross unrealized losses, less than 12 months	(322)	(23)
Estimated fair value, 12 months or more	3,284	4,106
Gross unrealized losses, 12 months or more	$ (427)	$ (815)