Benefit Plans Schedule of Benefit Obligations in Excess of Fair Value of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Pension plans with an accumulated benefit obligation in excess of plan assets:
Fair value of plan assets	$ 65	$ 56
Accumulated benefit obligation	113	95
Pension plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation	138	118
Pension Plan [Member]
Pension plans with a projected benefit obligation in excess of plan assets:
Fair value of plan assets	$ 66	$ 60