Employee Benefit Plans (Schedule of Amounts Recognized in Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax	$ 71	$ 59
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Prior Service Costs (Credit) Arising During Period, Net of Tax	0	0
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	71	59
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax	29	39
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Prior Service Costs (Credit) Arising During Period, Net of Tax	(8)	(9)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	$ 21	$ 30