Master Limited Partnership (Unit Repurchases) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Noncontrolling Interest [Line Items]
Average cost per share	$ 91.20	$ 62.65	$ 0
MPLX
Noncontrolling Interest [Line Items]
Number of common units repurchased	15	23	1
Cash paid for common units repurchased	$ 491	$ 630	$ 33
Average cost per share	$ 31.96	$ 27.52	$ 22.29

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