Employee Benefit Plans (Schedule of Changes in Fair Value of Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	$ 103
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	133	$ 103
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(87)	(76)
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	103	103
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	21	(6)
Defined Benefit Plan, Plan Assets, Contributions by Employer	17	14
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	0	0
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(8)	(8)
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	133	103
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(87)	(76)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0	0
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	0	0
Defined Benefit Plan, Plan Assets, Contributions by Employer	1	1
Defined Benefit Plan, Contributions by Plan Participants (Deprecated 2017-01-31)	0	0
Defined Benefit Plan, Benefits Paid (Deprecated 2017-01-31)	(1)	(1)
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0	0
Defined Benefit Plan, Funded (Unfunded) Status of Plan	$ (87)	$ (67)