Leases (Future Minimum Lease Payments Under Non-Cancellable Leases) (Details) $ in Millions	Sep. 30, 2020 USD ($)
Leases [Abstract]
Operating Leases, 2020 (excluding the nine months ended September 30, 2020)	$ 7
Operating Leases, 2021	22
Operating Leases, 2022	19
Operating Leases, 2023	15
Operating Leases, 2024	11
Operating Leases, Thereafter	85
Operating Leases, Total future minimum lease payments	158
Operating Leases, Less imputed interest	(42)
Operating Leases, Total	116
Finance Leases, 2020 (excluding the nine months ended September 30, 2020)	10
Finance Leases, 2021	33
Finance Leases, 2022	23
Finance Leases, 2023	16
Finance Leases, 2024	8
Finance Leases, Thereafter	4
Finance Leases, Total future minimum lease payments	94
Finance Leases, Less imputed interest	(3)
Finance Leases, Total	$ 92