Summary of Significant Accounting Policies (Schedule of Revenue from Contracts with Customers) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation Of Revenue [Line Items]
Total revenues from contracts with customers	$ 4,495	$ 2,578
Oil, Gas and NGL Sales [Member]
Disaggregation Of Revenue [Line Items]
Total revenues from contracts with customers	3,175	1,757
Oil, Gas and NGL Sales [Member] | Oil [Member]
Disaggregation Of Revenue [Line Items]
Total revenues from contracts with customers	2,406	1,331
Oil, Gas and NGL Sales [Member] | Gas [Member]
Disaggregation Of Revenue [Line Items]
Total revenues from contracts with customers	307	202
Oil, Gas and NGL Sales [Member] | NGL [Member]
Disaggregation Of Revenue [Line Items]
Total revenues from contracts with customers	462	224
Marketing and Midstream Revenues [Member]
Disaggregation Of Revenue [Line Items]
Total revenues from contracts with customers	1,320	821
Marketing and Midstream Revenues [Member] | Oil [Member]
Disaggregation Of Revenue [Line Items]
Total revenues from contracts with customers	776	499
Marketing and Midstream Revenues [Member] | Gas [Member]
Disaggregation Of Revenue [Line Items]
Total revenues from contracts with customers	209	147
Marketing and Midstream Revenues [Member] | NGL [Member]
Disaggregation Of Revenue [Line Items]
Total revenues from contracts with customers	$ 335	$ 175