Leases (Schedule of Right-of-use Assets and Lease Liabilities) (Details) - USD ($) $ in Millions		Mar. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Right-of-use assets, finance lease		$ 217	$ 220
Finance lease liabilities:
Current lease liabilities, finance lease	[1]	8	8
Long-term lease liabilities, finance lease		244	244
Total lease liabilities, finance lease		252	252
Right-of-use assets, operating lease		38	3
Operating lease liabilities:
Current lease liabilities, operating lease	[1]	23	1
Long-term lease liabilities, operating lease		16	2
Total lease liabilities, operating lease		39	3
Right-of-use assets		255	223
Lease liabilities:
Current lease liabilities	[1]	31	9
Long-term lease liabilities		260	246
Total lease liabilities		$ 291	$ 255

[1] Current lease liabilities are included in other current liabilities on the consolidated balance sheets.