Fair Value Measurements (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Corporate bonds - commingled funds [Member]
Fair value measurements of investments calculated at net asset value per share as well as the nature and risk of those investments
Fair Value	$ 32	$ 65
Unfunded Commitments	0	0
Redemption Frequency	Daily	Daily
Redemption Notice Period	1 to 3 days	1 to 3 days
Equity - commingled funds [Member]
Fair value measurements of investments calculated at net asset value per share as well as the nature and risk of those investments
Fair Value	48
Unfunded Commitments	0
Redemption Frequency	Daily/Monthly
Redemption Notice Period	Daily/7 days
Other - commingled funds [Member]
Fair value measurements of investments calculated at net asset value per share as well as the nature and risk of those investments
Fair Value	25	67
Unfunded Commitments	0	0
Redemption Frequency	Daily	Daily
Redemption Notice Period	Not applicable	Not applicable
Trust owned life insurance [Member]
Fair value measurements of investments calculated at net asset value per share as well as the nature and risk of those investments
Fair Value	87	86
Unfunded Commitments	0	0
Redemption Frequency	Daily	Daily
Redemption Notice Period	15 days	15 days
Money market funds [Member]
Fair value measurements of investments calculated at net asset value per share as well as the nature and risk of those investments
Fair Value	1,024	351
Unfunded Commitments	0	0
Redemption Frequency	Daily	Daily
Redemption Notice Period	Not applicable	Not applicable
Money market funds [Member]
Fair value measurements of investments calculated at net asset value per share as well as the nature and risk of those investments
Fair Value		2
Unfunded Commitments		$ 0
Redemption Frequency		Daily
Redemption Notice Period		Not applicable