Employee Benefits Schedule of Fair Value, Assets (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Money Market Funds, at Carrying Value	$ 7	$ 25
Equity securities:
Domestic	67	83
Defined Benefit Plan, Plan Assets, Amount		629
Financial Instruments, Owned, at Fair Value	7	25
Other Postretirement Benefit Plans assets: [Abstract]
Money market funds		3
Domestic equity securities - Other postretirement benefit plan assets at fair value		3
International equity securities - other post retirement assets at fair value		10
Private Equity Funds, US [Member]
Defined Benefit Plan Disclosure [Line Items]
Money Market Funds, at Carrying Value	5	5
Investments, Fair Value Disclosure	11	13
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Investments, Fair Value Disclosure	463	528
Fair Value, Inputs, Level 1 [Member]
Equity securities:
Domestic	67	83
Private equity funds	0	0
Defined Benefit Plan, Plan Assets, Amount	67	83
Financial Instruments, Owned, at Fair Value	128	43
Other Postretirement Benefit Plans assets: [Abstract]
Money market funds	3	3
Domestic equity securities - Other postretirement benefit plan assets at fair value	0	0
International equity securities - other post retirement assets at fair value	8	10
Other post retirement benefit plan assets total	11	13
Fair Value, Inputs, Level 2 [Member]
Equity securities:
Domestic	0	0
Private equity funds	0	0
Defined Benefit Plan, Plan Assets, Amount	0	0
Financial Instruments, Owned, at Fair Value	45	19
Other Postretirement Benefit Plans assets: [Abstract]
Money market funds	0	0
Domestic equity securities - Other postretirement benefit plan assets at fair value	3	3
International equity securities - other post retirement assets at fair value	0	0
Other post retirement benefit plan assets total	8	8
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Money Market Funds, at Carrying Value	0
Equity securities:
Domestic	0	0
Private equity funds	0	0
Defined Benefit Plan, Plan Assets, Amount	0	0
Financial Instruments, Owned, at Fair Value	3	0
Other Postretirement Benefit Plans assets: [Abstract]
Money market funds	0	0
Domestic equity securities - Other postretirement benefit plan assets at fair value	0	0
International equity securities - other post retirement assets at fair value	0	0
Other post retirement benefit plan assets total	0	0
Pension Plan [Member]
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	546	629	$ 559
Financial Instruments, Owned, at Fair Value	479	546
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Money Market Funds, at Carrying Value	4	4
Investments, Fair Value Disclosure	7	8
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	30	33	$ 30
Financial Instruments, Owned, at Fair Value	11	$ 12
Other Postretirement Benefit Plans assets: [Abstract]
Money market funds	3
Domestic equity securities - Other postretirement benefit plan assets at fair value	3
International equity securities - other post retirement assets at fair value	$ 8