Investments (Fair Values And Gross Unrealized Losses By Credit Rating Category Of Asset Backed Securities) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	$ 2,092	$ 2,387
Total, Unrealized Losses	278	478
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	330
Total, Unrealized Losses	(125)
Asset-Backed Securities [Member] | Aaa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	65
Total, Unrealized Losses	(4)
Asset-Backed Securities [Member] | Aa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	74
Total, Unrealized Losses	(8)
Asset-Backed Securities [Member] | A [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	29
Total, Unrealized Losses	(7)
Asset-Backed Securities [Member] | Baa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	30
Total, Unrealized Losses	(3)
Asset-Backed Securities [Member] | Below Investment Grade [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	131
Total, Unrealized Losses	(102)
Asset-Backed Securities [Member] | Not Rated [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	1
Total, Unrealized Losses	(1)
ABS CDO [Member] | Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	34
Total, Unrealized Losses	(57)
ABS CDO [Member] | Asset-Backed Securities [Member] | Aaa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	5
ABS CDO [Member] | Asset-Backed Securities [Member] | Aa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	5
ABS CDO [Member] | Asset-Backed Securities [Member] | A [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	7
Total, Unrealized Losses	(1)
ABS CDO [Member] | Asset-Backed Securities [Member] | Baa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	1
Total, Unrealized Losses	(3)
ABS CDO [Member] | Asset-Backed Securities [Member] | Below Investment Grade [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	16
Total, Unrealized Losses	(53)
Corporate CDO [Member] | Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	209
Total, Unrealized Losses	(62)
Corporate CDO [Member] | Asset-Backed Securities [Member] | Aaa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	42
Total, Unrealized Losses	(4)
Corporate CDO [Member] | Asset-Backed Securities [Member] | Aa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	65
Total, Unrealized Losses	(8)
Corporate CDO [Member] | Asset-Backed Securities [Member] | A [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	13
Total, Unrealized Losses	(6)
Corporate CDO [Member] | Asset-Backed Securities [Member] | Baa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	1
Corporate CDO [Member] | Asset-Backed Securities [Member] | Below Investment Grade [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	87
Total, Unrealized Losses	(43)
Corporate CDO [Member] | Asset-Backed Securities [Member] | Not Rated [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	1
Total, Unrealized Losses	(1)
Auto Loans [Member] | Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	10
Auto Loans [Member] | Asset-Backed Securities [Member] | Aa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	1
Auto Loans [Member] | Asset-Backed Securities [Member] | Baa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	9
Equipment Leases [Member] | Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	6
Equipment Leases [Member] | Asset-Backed Securities [Member] | Baa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	6
Small Business/ Student Loans [Member] | Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	27
Total, Unrealized Losses	(1)
Small Business/ Student Loans [Member] | Asset-Backed Securities [Member] | Aaa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	16
Small Business/ Student Loans [Member] | Asset-Backed Securities [Member] | Below Investment Grade [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	11
Total, Unrealized Losses	(1)
Other ABS [Member] | Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	44
Total, Unrealized Losses	(5)
Other ABS [Member] | Asset-Backed Securities [Member] | Aaa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	2
Other ABS [Member] | Asset-Backed Securities [Member] | Aa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	3
Other ABS [Member] | Asset-Backed Securities [Member] | A [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	9
Other ABS [Member] | Asset-Backed Securities [Member] | Baa [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	13
Other ABS [Member] | Asset-Backed Securities [Member] | Below Investment Grade [Member]
Schedule of Available-for-sale Securities [Line Items]
Total, Fair Value	17
Total, Unrealized Losses	$ (5)