Other Commitments And Other Operating Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments And Contingencies [Abstract]
2017	$ 44
2018	41
2019	39
2020	39
2021	36
Thereafter	168
Total	367
Payments for other commitments and operating leases	$ 43	$ 41	$ 42
Property Subject To Or Available For Operating Lease Expiration Beginning Date	2017
Property Subject To Or Available For Operating Lease Expiration Ending Date	2052