Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net income (loss)	$ (888.2)	$ (1,409.7)	$ 249.7
Adjustments to reconcile net income (loss) to net cash provided by operating activities, net of assets acquired or liabilities assumed:
Depreciation and amortization	503.9	387.3	284.3
Impairments	873.3	1,563.4
Accretion	0.6	0.6	0.5
(Gain) loss on disposition of assets	13.2	1.2	(0.1)
Gain on extinguishment of debt			(3.2)
Deferred tax expense	2.1	22.6	67.4
Non-cash unit-based compensation	30.3	36.1	19.6
(Gain) loss on derivatives recognized in net income (loss)	11.1	(9.4)	(22.1)
Cash settlements on derivatives	10.5	17.1	(0.3)
Amortization of debt issue costs	3.9	3.3	1.9
Amortization of net (premium) discounts on notes	49.5	(2.9)	(2.9)
Redeemable non-controlling interest expense	0.3	(1.8)
Distribution of earnings from unconsolidated affiliates	3.1	21.6	7.0
(Income) loss from unconsolidated affiliates	19.9	(20.4)	(18.9)
Changes in assets and liabilities net of assets acquired and liabilities assumed:
Accounts receivable, accrued revenue and other	(118.1)	197.5	(98.9)
Natural gas and NGLs inventory, prepaid expenses and other	18.7	(6.7)	(8.2)
Accounts payable, accrued gas and crude oil purchases and other accrued liabilities	132.3	(171.4)	(16.9)
Net cash provided by operating activities	666.4	628.4	458.9
Cash flows from investing activities, net of assets acquired and liabilities assumed:
Additions to property and equipment	(663.0)	(572.3)	(796.0)
Acquisition of business, net of cash acquired	(791.5)	(524.2)	(357.9)
Proceeds from insurance settlement	0.3	2.9
Proceeds from sale of property	93.1	1.0	0.1
Investment in unconsolidated affiliates	(73.8)	(25.8)	(5.7)
Distribution from unconsolidated affiliates in excess of earnings	54.6	21.1	10.9
Net cash used in investing activities	(1,380.3)	(1,097.3)	(1,148.6)
Cash flows from financing activities:
Proceeds from borrowings	2,150.4	3,204.4	3,367.8
Payments on borrowings	(1,917.5)	(2,134.3)	(2,792.7)
Payments on capital lease obligations	(6.6)	(3.6)	(3.0)
Increase (decrease) in drafts payable		(12.7)	10.2
Debt financing costs	(4.7)	(9.6)	(19.7)
Redeemable non-controlling interest	(3.0)
Conversion of restricted units, net of units withheld for taxes	(1.2)	(2.9)	(1.1)
Conversion of Partnership's restricted units, net of units withheld for taxes	(1.2)	(2.5)	(0.7)
Proceeds from issuance of Partnership's common units	167.5	24.4	412.0
Distributions to non-controlling partners	(384.2)	(359.5)	(204.3)
Distribution to members	(185.4)	(162.8)	(89.0)
Distributions to Predecessor			(21.3)
Contributions from Devon	1.5	27.8	105.7
Proceeds from exercise of Partnership unit options		0.1	0.4
Proceeds from issuance of Preferred Units	724.1
Purchase of non-controlling interest			(12.5)
Distribution to Devon for VEX interests transferred		(166.7)
Contributions by non-controlling interest	167.9	16.4	6.3
Net cash provided by financing activities	707.6	418.5	758.1
Cash flow from discontinued operations:
Net cash provided by operating activities			5.0
Net cash used in investing activities			(0.6)
Net cash used in financing activities-net distributions to Devon and non-controlling interests			(4.4)
Net increase (decrease) in cash and cash equivalents	(6.3)	(50.4)	68.4
Cash and cash equivalents, beginning of period	18.0	68.4
Cash and cash equivalents, end of period	11.7	18.0	68.4
Cash paid for interest	133.7	110.0	55.8
Cash paid (refund) for income taxes	$ (7.0)	$ 13.7	$ 7.5