Employee Benefit Plans, Net Periodic Benefit Costs Amortized from Accumulated Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Pension Plans [Member]
Pension and Other Postretirement Benefit Plans Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year
Amortization of prior service cost (credit)	$ (3)
Amortization of net actuarial loss	33
Total	36
Other Postretirement Benefit Plans [Member]
Pension and Other Postretirement Benefit Plans Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year
Amortization of prior service cost (credit)	23
Amortization of net actuarial loss	1
Total	$ (22)