Acquisitions and Dispositions - Acquisitions (Details) $ in Millions		1 Months Ended	3 Months Ended
	Feb. 14, 2017 USD ($) a bbl / d market_interconnect mi	Feb. 28, 2017 USD ($)	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)
Business Acquisition [Line Items]
Cash paid in connection with acquisitions			$ 1,254	$ 85
Acquisition related costs			5
ACC Acquisition
Business Acquisition [Line Items]
Cash paid in connection with acquisitions	$ 1,217
Length of gathering and transmission lines (in miles) | mi	515
Number of market interconnects | market_interconnect	5
Additional volume enhancements to gathering system (in bbl per day) | bbl / d	350,000
Area of acreage dedications (in acres) | a	315,000
Acquisition related costs			$ 5
Propane marine terminal
Business Acquisition [Line Items]
Cash paid in connection with acquisitions		$ 41