Revenue Recognition (Summary of Revenue Disaggregation) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 794	$ 970
United States [Member]
Disaggregation of Revenue [Line Items]
Revenue	638	779
Canada [Member]
Disaggregation of Revenue [Line Items]
Revenue	50	68
International [Member]
Disaggregation of Revenue [Line Items]
Revenue	106	123
Upstream [Member]
Disaggregation of Revenue [Line Items]
Revenue	222	312
Upstream [Member] | United States [Member]
Disaggregation of Revenue [Line Items]
Revenue	139	206
Upstream [Member] | Canada [Member]
Disaggregation of Revenue [Line Items]
Revenue	37	46
Upstream [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Revenue	46	60
Midstream [Member]
Disaggregation of Revenue [Line Items]
Revenue	119	147
Midstream [Member] | United States [Member]
Disaggregation of Revenue [Line Items]
Revenue	110	133
Midstream [Member] | Canada [Member]
Disaggregation of Revenue [Line Items]
Revenue	4	6
Midstream [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Revenue	5	8
Gas Utilities [Member]
Disaggregation of Revenue [Line Items]
Revenue	202	214
Gas Utilities [Member] | United States [Member]
Disaggregation of Revenue [Line Items]
Revenue	199	204
Gas Utilities [Member] | Canada [Member]
Disaggregation of Revenue [Line Items]
Revenue	3	10
Downstream [Member]
Disaggregation of Revenue [Line Items]
Revenue	251	297
Downstream [Member] | United States [Member]
Disaggregation of Revenue [Line Items]
Revenue	190	236
Downstream [Member] | Canada [Member]
Disaggregation of Revenue [Line Items]
Revenue	6	6
Downstream [Member] | International [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 55	$ 55