Available-For-Sale Securities (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Schedule of Available-for-sale Securities
Cost Basis	$ 1,483		$ 1,483		$ 1,479
Unrealized pretax net gains (losses)	128		128		107
Fair Value	1,611		1,611		1,586
Charges for other than temporary decIines in the value of securities	0	0	1	1
U.S. treasury bonds
Schedule of Available-for-sale Securities
Cost Basis	11		11		10
Unrealized pretax net gains (losses)	0		0		0
Fair Value	11		11		10
Other U.S. and non-U.S. government bonds
Schedule of Available-for-sale Securities
Cost Basis	125		125		144
Unrealized pretax net gains (losses)	1		1		2
Fair Value	126		126		146
Corporate bonds
Schedule of Available-for-sale Securities
Cost Basis	648		648		626
Unrealized pretax net gains (losses)	24		24		38
Fair Value	672		672		664
Asset-backed Securities
Schedule of Available-for-sale Securities
Cost Basis	75		75		96
Unrealized pretax net gains (losses)	0		0		0
Fair Value	75		75		96
U.S. governmental agency mortgage-backed securities
Schedule of Available-for-sale Securities
Cost Basis	336		336		291
Unrealized pretax net gains (losses)	1		1		8
Fair Value	337		337		299
Residential
Schedule of Available-for-sale Securities
Cost Basis	21		21		26
Unrealized pretax net gains (losses)	0		0		(1)
Fair Value	21		21		25
Commercial
Schedule of Available-for-sale Securities
Cost Basis	87		87		117
Unrealized pretax net gains (losses)	6		6		10
Fair Value	93		93		127
Large capitalization value
Schedule of Available-for-sale Securities
Cost Basis	158		158		147
Unrealized pretax net gains (losses)	73		73		38
Fair Value	231		231		185
Smaller company growth
Schedule of Available-for-sale Securities
Cost Basis	22		22		22
Unrealized pretax net gains (losses)	23		23		12
Fair Value	$ 45		$ 45		$ 34