Employee Benefits Schedule of Fair Value, Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Plan [Member]
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	$ 753	$ 695	$ 546
Pension Plan [Member] | Money market funds
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	6	5
Pension Plan [Member] | Collective trust funds
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	692	632
Pension Plan [Member] | Private equity funds
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	6	9
Pension Plan [Member] | Defined Benefit Plan, Equity Securities, US
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	49	49
Pension Plan [Member] | Fair Value, Inputs, Level 1 [Member]
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	49	49
Pension Plan [Member] | Fair Value, Inputs, Level 1 [Member] | Defined Benefit Plan, Equity Securities, US
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	49	49
Pension Plan [Member] | Fair Value, Inputs, Level 2 [Member]
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan [Member] | Fair Value, Inputs, Level 2 [Member] | Defined Benefit Plan, Equity Securities, US
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan [Member] | Fair Value, Inputs, Level 3 [Member]
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan [Member] | Fair Value, Inputs, Level 3 [Member] | Defined Benefit Plan, Equity Securities, US
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	0	0
Pension Plan [Member] | Other
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	704	646
Pension Plan [Member] | Other | Money market funds
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	6	5
Pension Plan [Member] | Other | Collective trust funds
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	692	632
Pension Plan [Member] | Other | Private equity funds
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	6	9
Other Postretirement Benefit Plans [Member]
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	35	34	$ 30
Other Postretirement Benefit Plans [Member] | Money market funds
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	5	5
Other Postretirement Benefit Plans [Member] | Money Market Funds
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	4	4
Other Postretirement Benefit Plans [Member] | Collective trust funds
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	9	8
Other Postretirement Benefit Plans [Member] | Defined Benefit Plan, Equity Securities, US
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	3	3
Other Postretirement Benefit Plans [Member] | Defined Benefit Plan, Equity Securities, Non-US
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	9	9
Other Postretirement Benefit Plans [Member] | US Government Agencies Debt Securities
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	5	5
Other Postretirement Benefit Plans [Member] | Fair Value, Inputs, Level 1 [Member]
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	13	13
Other Postretirement Benefit Plans [Member] | Fair Value, Inputs, Level 1 [Member] | Money Market Funds
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	4	4
Other Postretirement Benefit Plans [Member] | Fair Value, Inputs, Level 1 [Member] | Defined Benefit Plan, Equity Securities, US
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefit Plans [Member] | Fair Value, Inputs, Level 1 [Member] | Defined Benefit Plan, Equity Securities, Non-US
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	9	9
Other Postretirement Benefit Plans [Member] | Fair Value, Inputs, Level 1 [Member] | US Government Agencies Debt Securities
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefit Plans [Member] | Fair Value, Inputs, Level 2 [Member]
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	8	8
Other Postretirement Benefit Plans [Member] | Fair Value, Inputs, Level 2 [Member] | Money Market Funds
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefit Plans [Member] | Fair Value, Inputs, Level 2 [Member] | Defined Benefit Plan, Equity Securities, US
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	3	3
Other Postretirement Benefit Plans [Member] | Fair Value, Inputs, Level 2 [Member] | Defined Benefit Plan, Equity Securities, Non-US
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefit Plans [Member] | Fair Value, Inputs, Level 2 [Member] | US Government Agencies Debt Securities
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	5	5
Other Postretirement Benefit Plans [Member] | Fair Value, Inputs, Level 3 [Member]
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefit Plans [Member] | Fair Value, Inputs, Level 3 [Member] | Money Market Funds
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefit Plans [Member] | Fair Value, Inputs, Level 3 [Member] | Defined Benefit Plan, Equity Securities, US
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefit Plans [Member] | Fair Value, Inputs, Level 3 [Member] | Defined Benefit Plan, Equity Securities, Non-US
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefit Plans [Member] | Fair Value, Inputs, Level 3 [Member] | US Government Agencies Debt Securities
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	0	0
Other Postretirement Benefit Plans [Member] | Other
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	14	13
Other Postretirement Benefit Plans [Member] | Other | Money market funds
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	5	5
Other Postretirement Benefit Plans [Member] | Other | Collective trust funds
Equity securities:
Defined Benefit Plan, Plan Assets, Amount	$ 9	$ 8