Employee Benefit Plans (Information for Pension Plans with a Projected and Accumulated Benefit Obligation in Excess of Plan Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Pension Plan with Project Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation	$ 2,997	$ 2,895
Fair value of plan assets	62	59
Information On Pension Plans With Accumulated Benefit Obligation In Excess Of Plan Assets [Abstract]
Accumulated benefit obligation	2,760	2,697
Fair value of plan assets	$ 7	$ 6