Leases (Maturities of Lease Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Operating Leases
2021	$ 141
2022	125
2023	114
2024	102
2025	92
After 2025	733
Gross Total	1,307
Imputed Discount	(578)
Total	729	$ 512
Financing Leases
2021	13
2022	16
2023	21
2024	24
2025	12
After 2025	169
Gross Total	255
Imputed Discount	(82)
Total	$ 173	$ 280