Reportable Segments Operating expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Operating expenses(a)	$ 9,287	$ 5,398	$ 6,280
Operating Segments | Natural Gas Pipelines
Segment Reporting Information [Line Items]
Operating expenses(a)	7,000	3,457	4,213
Operating Segments | Products Pipelines
Segment Reporting Information [Line Items]
Operating expenses(a)	1,239	779	684
Operating Segments | Terminals
Segment Reporting Information [Line Items]
Operating expenses(a)	793	762	888
Operating Segments | CO2
Segment Reporting Information [Line Items]
Operating expenses(a)	289	404	496
Intersegment Eliminations
Segment Reporting Information [Line Items]
Operating expenses(a)	$ (34)	$ (4)	$ (1)