Revenue Recognition Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Operating Lease, Lease Income	$ 294	$ 218
Revenues from contracts with customers	2,686	3,172
Other revenues	420	257
Total revenues	3,106	3,429
Natural Gas Pipelines
Disaggregation of Revenue [Line Items]
Total revenues	1,861	2,192
Products Pipelines
Disaggregation of Revenue [Line Items]
Total revenues	495	424
Terminals
Disaggregation of Revenue [Line Items]
Total revenues	441	508
CO2
Disaggregation of Revenue [Line Items]
Total revenues	309	305
Operating Segments | Natural Gas Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,695	2,116
Other revenues	180	85
Total revenues	1,875	2,201
Operating Segments | Products Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	448	381
Other revenues	47	43
Total revenues	495	424
Operating Segments | Terminals
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	313	400
Other revenues	129	109
Total revenues	442	509
Operating Segments | CO2
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	245	285
Other revenues	64	20
Total revenues	309	305
Corporate and eliminations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(15)	(10)
Other revenues	0	0
Total revenues	(15)	(10)
Firm services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,133	1,259
Firm services | Operating Segments | Natural Gas Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	865	930
Firm services | Operating Segments | Products Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	79	80
Firm services | Operating Segments | Terminals
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	189	250
Firm services | Operating Segments | CO2
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Firm services | Corporate and eliminations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	(1)
Fee-based services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	587	590
Fee-based services | Operating Segments | Natural Gas Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	193	192
Fee-based services | Operating Segments | Products Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	260	235
Fee-based services | Operating Segments | Terminals
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	121	148
Fee-based services | Operating Segments | CO2
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	13	16
Fee-based services | Corporate and eliminations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	(1)
Total services revenues
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,720	1,849
Total services revenues | Operating Segments | Natural Gas Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,058	1,122
Total services revenues | Operating Segments | Products Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	339	315
Total services revenues | Operating Segments | Terminals
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	310	398
Total services revenues | Operating Segments | CO2
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	13	16
Total services revenues | Corporate and eliminations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	(2)
Natural gas sales
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	499	753
Natural gas sales | Operating Segments | Natural Gas Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	501	754
Natural gas sales | Operating Segments | Products Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Natural gas sales | Operating Segments | Terminals
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Natural gas sales | Operating Segments | CO2
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	1
Natural gas sales | Corporate and eliminations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(2)	(2)
Product Other Than Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	467	570
Product Other Than Natural Gas [Member] | Operating Segments | Natural Gas Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	136	240
Product Other Than Natural Gas [Member] | Operating Segments | Products Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	109	66
Product Other Than Natural Gas [Member] | Operating Segments | Terminals
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3	2
Product Other Than Natural Gas [Member] | Operating Segments | CO2
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	232	268
Product Other Than Natural Gas [Member] | Corporate and eliminations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(13)	(6)
Commodity sales
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	966	1,323
Total revenues	1,067	1,349
Commodity sales | Operating Segments | Natural Gas Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	637	994
Commodity sales | Operating Segments | Products Pipelines
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	109	66
Commodity sales | Operating Segments | Terminals
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3	2
Commodity sales | Operating Segments | CO2
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	232	269
Commodity sales | Corporate and eliminations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(15)	(8)
Revenues-Commodity sales
Disaggregation of Revenue [Line Items]
Gain/(loss) recognized in income on derivative and related hedged item	$ 104	$ 23