Employee Benefits Schedule of Expected Benefit Payments (Details) $ in Millions	Dec. 31, 2016 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	$ 45
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	46
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	48
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	48
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	50
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	261
Pension Plans, Defined Benefit [Member]
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	39
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	40
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	42
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	43
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	229
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	5
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	5
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	5
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	22
Non Qualified Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	3
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	2
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	3
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	2
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	2
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	$ 10