Contingencies And Commitments (Future Minimum Lease Payments) (Details) $ in Millions	Mar. 31, 2019 USD ($)
Operating Leases
2019	$ 32
2020	37
2021	36
2022	32
2023	29
Thereafter	67
Total future minimum lease payments	233
Less: Amount representing interest	29
Present value of minimum lease payments	204
Finance Leases
2019	93
2020	57
2021	67
2022	67
2023	91
Thereafter	28
Total future minimum lease payments	403
Less: Amount representing interest	39
Present value of minimum lease payments	$ 364