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, 2012
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	57
Total	60
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)	(13)
Amortization of net actuarial loss	0
Total	$ (13)