Investment Securities (Schedule of Unrealized Loss on Investments) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	$ 2,684	$ 10,118
Available-for-sale Securities, Unrealized Loss Less than 12 months	(40)	(482)
Available-for-sale Securities, Fair value 12 months or longer	5,524	204
Available-for-sale Securities, Unrealized Loss 12 months or longer	(232)	(26)
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	2,429	9,951
Available-for-sale Securities, Unrealized Loss Less than 12 months	(19)	(470)
Available-for-sale Securities, Fair value 12 months or longer	5,510	104
Available-for-sale Securities, Unrealized Loss 12 months or longer	(230)	(10)
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	0	1,405
Available-for-sale Securities, Unrealized Loss Less than 12 months	0	(69)
Available-for-sale Securities, Fair value 12 months or longer	1,245	0
Available-for-sale Securities, Unrealized Loss 12 months or longer	(28)	0
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	21	212
Available-for-sale Securities, Unrealized Loss Less than 12 months	0	(1)
Available-for-sale Securities, Fair value 12 months or longer	0	0
Available-for-sale Securities, Unrealized Loss 12 months or longer	0	0
Foreign Government Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	43	114
Available-for-sale Securities, Unrealized Loss Less than 12 months	0	(3)
Available-for-sale Securities, Fair value 12 months or longer	0	0
Available-for-sale Securities, Unrealized Loss 12 months or longer	0	0
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	1,428	7,503
Available-for-sale Securities, Unrealized Loss Less than 12 months	(12)	(388)
Available-for-sale Securities, Fair value 12 months or longer	4,229	100
Available-for-sale Securities, Unrealized Loss 12 months or longer	(201)	(10)
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	699	407
Available-for-sale Securities, Unrealized Loss Less than 12 months	(3)	(3)
Available-for-sale Securities, Fair value 12 months or longer	16	1
Available-for-sale Securities, Unrealized Loss 12 months or longer	0	0
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	238	310
Available-for-sale Securities, Unrealized Loss Less than 12 months	(4)	(6)
Available-for-sale Securities, Fair value 12 months or longer	20	3
Available-for-sale Securities, Unrealized Loss 12 months or longer	(1)	0
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Fair value Less than 12 months	255	167
Available-for-sale Securities, Unrealized Loss Less than 12 months	(21)	(12)
Available-for-sale Securities, Fair value 12 months or longer	14	100
Available-for-sale Securities, Unrealized Loss 12 months or longer	$ (2)	$ (16)