Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Jun. 30, 2016
Income Tax [Line Items]
Valuation allowance against U.S. deferred tax assets, percent						100.00%
Deferred tax assets, valuation allowance		$ 808				$ 967	$ 467
Interest associated with tax examinations	$ 34
Scenario Plan [Member]
Income Tax [Line Items]
Unrecognized tax benefits	85
General Partner And EnLink [Member]
Income Tax [Line Items]
Goodwill impairments		$ 873	$ 576	$ 873	$ 576
Goodwill and intangibles impairments			$ 799
United States [Member]
Income Tax [Line Items]
Change in deferred tax valuation allowance	(479)
Canada [Member]
Income Tax [Line Items]
Change in deferred tax valuation allowance	$ 71