v3.6.0.2

Subsequent Events (Details) $ / shares in Units, $ in Millions													12 Months Ended
	Feb. 10, 2017 USD ($) shares	Feb. 09, 2017 shares	Feb. 06, 2017 USD ($)	Jan. 11, 2017 $ / shares	Nov. 24, 2016 $ / shares	Aug. 24, 2016 $ / shares	May 25, 2016 $ / shares	Feb. 29, 2016 $ / shares	Nov. 30, 2015 $ / shares	Aug. 27, 2015 $ / shares	May 27, 2015 $ / shares	Feb. 27, 2015 $ / shares	Dec. 31, 2016 shares	Dec. 31, 2015 shares	Dec. 31, 2014 shares
Subsequent events
Cash distribution declared | $ / shares					$ 0.2650	$ 0.2500	$ 0.2350	$ 0.2200	$ 0.2050	$ 0.1900	$ 0.1800	$ 0.0943
Subordinated units													75,941,000	75,941,000	75,941,000
Subsequent event
Subsequent events
Cash distribution declared | $ / shares				$ 0.28
Subordinated units		75,940,957
Common units conversion ratio		1
Number of shares of common stock sold	6,900,000
Net proceeds received from issuance shares of common units | $	$ 223
Subsequent event | Appalachia Joint venture
Subsequent events
Ownership percentage			50.00%
Percentage of interest held by joint venture in third party fractionator in Ohio			33.33%
Contribution to joint venture | $			$ 155
Subsequent event | Appalachia Joint venture | Mark West
Subsequent events
Ownership percentage			50.00%

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Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.

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