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Acquisitions (Schedule of Consideration Paid to Equity Holders of Indigo) (Details) - USD ($) $ / shares in Units, $ in Millions		9 Months Ended
	Sep. 01, 2021	Sep. 30, 2022	Sep. 30, 2021
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Cash consideration		$ 0	$ 373
Indigo Natural Resources, LLC
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Shares of Southwestern common stock issued (in shares)	337,827,171
NYSE closing price per share of Southwestern common shares (in dollars per share)	$ 4.70
Value of Southwestern's stock issued as consideration	$ 1,588
Cash consideration	373
Total consideration	$ 1,961