Postretirement Benefits (Details 10) (Employee pension plan, USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Fair value measurements of pension plan assets
Total	$ 411	$ 348	$ 328
Total
Fair value measurements of pension plan assets
Total	411	348
Level 1
Fair value measurements of pension plan assets
Total	3	2
Level 2
Fair value measurements of pension plan assets
Total	408	346
Level 3
Fair value measurements of pension plan assets
Total	0	0
Total equity securities | Total
Fair value measurements of pension plan assets
Total	255	208
Total equity securities | Level 1
Fair value measurements of pension plan assets
Total	0	0
Total equity securities | Level 2
Fair value measurements of pension plan assets
Total	255	208
Total equity securities | Level 3
Fair value measurements of pension plan assets
Total	0	0
U.S. equity securities | Total
Fair value measurements of pension plan assets
Total	168	140
U.S. equity securities | Level 1
Fair value measurements of pension plan assets
Total	0	0
U.S. equity securities | Level 2
Fair value measurements of pension plan assets
Total	168	140
U.S. equity securities | Level 3
Fair value measurements of pension plan assets
Total	0	0
Non-U.S. equity security | Total
Fair value measurements of pension plan assets
Total	87	68
Non-U.S. equity security | Level 1
Fair value measurements of pension plan assets
Total	0	0
Non-U.S. equity security | Level 2
Fair value measurements of pension plan assets
Total	87	68
Non-U.S. equity security | Level 3
Fair value measurements of pension plan assets
Total	0	0
Debt securities - U.S. fixed income | Total
Fair value measurements of pension plan assets
Total	153	138
Debt securities - U.S. fixed income | Level 1
Fair value measurements of pension plan assets
Total	0	0
Debt securities - U.S. fixed income | Level 2
Fair value measurements of pension plan assets
Total	153	138
Debt securities - U.S. fixed income | Level 3
Fair value measurements of pension plan assets
Total	0	0
Other | Total
Fair value measurements of pension plan assets
Total	3	2
Other | Level 1
Fair value measurements of pension plan assets
Total	3	2
Other | Level 2
Fair value measurements of pension plan assets
Total	0	0
Other | Level 3
Fair value measurements of pension plan assets
Total	$ 0	$ 0