Acquisitions - (Schedule of Consideration Paid to Equity Holders of GEPH) (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Dec. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Cash consideration		$ 0	$ 0	$ 1,642
GEPH Merger
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Shares of Southwestern common stock issued in respect of outstanding common stock and stock-based awards (in shares)	99,337,748
NYSE closing price per share of Southwestern common shares (in dollars per share)	$ 4.66			$ 4.66
Business acquisition, equity interest issued or issuable, value assigned	$ 463			$ 463
Cash consideration	1,263
Total consideration	1,726
Customary post-close cash consideration, adjustment	$ (6)