Employee Benefits Schedule of Expected Benefit Payments (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	$ 37
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	38
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	40
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	43
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	44
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	243
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	31
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	32
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	34
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	36
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	37
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	209
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	4
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	4
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	4
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	4
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	5
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	23
Non Qualified Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	2
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	2
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	2
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	3
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	2
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	$ 11