Acquisitions (Schedule of Consideration Paid to Equity Holders of Indigo) (Details) - Indigo Natural Resources, LLC - USD ($) $ / shares in Units, $ in Millions		1 Months Ended
Sep. 01, 2021	Sep. 30, 2021
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Shares of Southwestern common stock issued (in shares)	337,827,171	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

Value of equity interests (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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