Segment Information - Segment Financial Data (Details) $ in Millions	3 Months Ended		6 Months Ended		9 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) segment	Jun. 30, 2021 USD ($)	Jun. 30, 2022 segment	Sep. 30, 2021 segment
Segment Reporting Information
Operating segments number | segment			2		2	3
Revenues:
Revenues	$ 16,359	$ 9,930	$ 30,053	$ 18,313
Segment Reporting, Disclosure of Other Information about Entity's Reportable Segments
Equity earnings in unconsolidated entities	104	33	201	121
Segment Adjusted EBITDA	614	574	1,227	1,117
Maintenance capital expenditures	43	37	70	73
Operating Segments
Revenues:
Revenues	16,510	10,009	30,323	18,501
Intersegment Revenues Elimination
Revenues:
Revenues	(151)	(79)	(270)	(188)
Product sales revenues
Revenues:
Revenues	16,007	9,623	29,388	17,706
Product sales revenues | Intersegment Revenues Elimination
Revenues:
Revenues	(143)	(75)	(254)	(178)
Services revenues
Revenues:
Revenues	352	307	665	607
Services revenues | Intersegment Revenues Elimination
Revenues:
Revenues	(8)	(4)	(16)	(10)
Crude Oil
Segment Reporting, Disclosure of Other Information about Entity's Reportable Segments
Equity earnings in unconsolidated entities	104	33	201	121
Segment Adjusted EBITDA	494	553	946	1,027
Maintenance capital expenditures	25	23	45	52
Crude Oil | Operating Segments
Revenues:
Revenues	15,940	9,779	29,019	17,632
Crude Oil | Product sales revenues | Operating Segments
Revenues:
Revenues	15,625	9,500	28,435	17,086
Crude Oil | Services revenues | Operating Segments
Revenues:
Revenues	315	279	584	546
NGL
Segment Reporting, Disclosure of Other Information about Entity's Reportable Segments
Segment Adjusted EBITDA	120	21	281	90
Maintenance capital expenditures	18	14	25	21
NGL | Operating Segments
Revenues:
Revenues	570	230	1,304	869
NGL | Product sales revenues | Operating Segments
Revenues:
Revenues	525	198	1,207	798
NGL | Services revenues | Operating Segments
Revenues:
Revenues	$ 45	$ 32	$ 97	$ 71