Non-Mineral Leases (Lease Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Non-Mineral Leases [Abstract]
Operating lease cost	$ 278	$ 321	$ 341
Finance lease cost: Amortization of right-of-use-assets	148	163	99
Finance lease cost: Interest on lease liabilities	27	34	37
Short-term lease cost	21	42	77
Total lease cost	$ 474	$ 560	$ 554