Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation	$ 212	$ 174
Defined Contribution Plan, Cost	16	15	$ 14
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	17	14	19
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	18
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	6	$ 6	$ 5
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	$ 2
Debt Securities [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	40.00%
Equity Securities [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Target Allocation Percentage of Assets, Equity Securities	60.00%