Employee Benefits Schedule of Expected Benefit Payments (Details) $ in Millions	Dec. 31, 2018 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	$ 48
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	49
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	51
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	52
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	53
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	270
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	41
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	42
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	44
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	45
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	45
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	238
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	5
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	6
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	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	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