Fair Value Measurements (Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Assets:
Deferred compensation plan assets	$ 64	$ 85
Investment in affiliate	85	187
Contingent consideration	27	91
Total assets	251	395
Liabilities:
Total recurring fair value measurements	136	375
Investment in affiliate	85	187
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Deferred compensation plan assets	64	85
Investment in affiliate	85	187
Contingent consideration	0	0
Total assets	149	272
Liabilities:
Total recurring fair value measurements	149	272
Investment in affiliate	85	187
Significant Other Observable Inputs (Level 2)
Assets:
Deferred compensation plan assets	0	0
Investment in affiliate	0	0
Contingent consideration	27	91
Total assets	102	123
Liabilities:
Total recurring fair value measurements	(13)	103
Investment in affiliate	0	0
Significant Unobservable Inputs (Level 3)
Assets:
Deferred compensation plan assets	0	0
Investment in affiliate	0	0
Contingent consideration	0	0
Total assets	0	0
Liabilities:
Total recurring fair value measurements	0	0
Investment in affiliate	0	0
Commodity price derivatives
Assets:
Commodity price derivatives	75	32
Liabilities:
Commodity price derivatives	115	20
Commodity price derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Commodity price derivatives	0	0
Liabilities:
Commodity price derivatives	0	0
Commodity price derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Commodity price derivatives	75	32
Liabilities:
Commodity price derivatives	115	20
Commodity price derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Commodity price derivatives	0	0
Liabilities:
Commodity price derivatives	$ 0	$ 0