Investment Securities (Schedule of Available-for-sale Securities Reconciliation) (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 16,526,000,000	$ 17,425,000,000
Available-for-sale Securities, Gross Unrealized Gains	160,000,000	166,000,000
Available-for-sale Securities, Gross Unrealized Losses	(359,000,000)	(508,000,000)
Available-for-sale Securities	16,327,000,000	17,083,000,000
Total agency backed bonds	7,647,000,000	8,266,000,000
Deposit Assets	15,000,000	15,000,000
Cash Equivalents, at Carrying Value	2,000,000,000	2,400,000,000
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	15,611,000,000	16,527,000,000
Available-for-sale Debt Securities Gross Unrealized Gain	114,000,000	92,000,000
Available-for-sale Debt Securities, Gross Unrealized Loss	(336,000,000)	(480,000,000)
Available-for-sale Securities, Debt Securities	15,389,000,000	16,139,000,000
US Treasury and Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	1,293,000,000	1,495,000,000
Available-for-sale Debt Securities Gross Unrealized Gain	1,000,000	1,000,000
Available-for-sale Debt Securities, Gross Unrealized Loss	(46,000,000)	(69,000,000)
Available-for-sale Securities, Debt Securities	1,248,000,000	1,427,000,000
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	331,000,000	316,000,000
Available-for-sale Debt Securities Gross Unrealized Gain	7,000,000	0
Available-for-sale Debt Securities, Gross Unrealized Loss	0	(1,000,000)
Available-for-sale Securities, Debt Securities	338,000,000	315,000,000
Foreign Government Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	275,000,000	287,000,000
Available-for-sale Debt Securities Gross Unrealized Gain	6,000,000	4,000,000
Available-for-sale Debt Securities, Gross Unrealized Loss	(1,000,000)	(3,000,000)
Available-for-sale Securities, Debt Securities	280,000,000	288,000,000
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	10,475,000,000	11,131,000,000
Available-for-sale Debt Securities Gross Unrealized Gain	54,000,000	49,000,000
Available-for-sale Debt Securities, Gross Unrealized Loss	(285,000,000)	(398,000,000)
Available-for-sale Securities, Debt Securities	10,244,000,000	10,782,000,000
Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	61,000,000	39,000,000
Available-for-sale Debt Securities Gross Unrealized Gain	1,000,000	0
Available-for-sale Debt Securities, Gross Unrealized Loss	0	0
Available-for-sale Securities, Debt Securities	62,000,000	39,000,000
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	2,121,000,000	2,207,000,000
Available-for-sale Debt Securities Gross Unrealized Gain	15,000,000	15,000,000
Available-for-sale Debt Securities, Gross Unrealized Loss	(2,000,000)	(3,000,000)
Available-for-sale Securities, Debt Securities	2,134,000,000	2,219,000,000
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities, Amortized Cost Basis	1,055,000,000	1,052,000,000
Available-for-sale Debt Securities Gross Unrealized Gain	30,000,000	23,000,000
Available-for-sale Debt Securities, Gross Unrealized Loss	(2,000,000)	(6,000,000)
Available-for-sale Securities, Debt Securities	1,083,000,000	1,069,000,000
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Equity Securities, Amortized Cost Basis	915,000,000	898,000,000
Available-for-sale Equity Securities, Gross Unrealized Gain	46,000,000	74,000,000
Available-for-sale Equity Securities, Gross Unrealized Loss	(23,000,000)	(28,000,000)
Available-for-sale Securities, Equity Securities	$ 938,000,000	$ 944,000,000