Postretirement Benefit Plans (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Amount recognized in consolidated in accumulated other comprehensive income
Net actuarial loss	$ 205	$ 145
Prior service cost (benefit)	5	8
Total	210	153
Pension [Member]
Amount recognized in consolidated in accumulated other comprehensive income
Net actuarial loss	147	100
Prior service cost (benefit)	6	9
Total	153	109
Other Benefits [Member]
Amount recognized in consolidated in accumulated other comprehensive income
Net actuarial loss	58	45
Prior service cost (benefit)	(1)	(1)
Total	$ 57	$ 44