Other Information (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Other Current Assets:
Natural gas and NGLs inventory	$ 41.3	$ 30.1
Secured term loan receivable from contract restructuring, net of discount of $1.1	19.4	0.0
Secured term loan receivable, discount	1.1	0.0
Prepaid expenses and other	13.5	11.1
Natural gas and NGLs inventory, prepaid expenses, and other	74.2	41.2
Other Current Liabilities:
Accrued interest	37.5	35.6
Accrued wages and benefits, including taxes	37.2	30.4
Accrued ad valorem taxes	28.1	27.8
Capital expenditure accruals	50.6	48.8
Onerous performance obligations	9.0	15.2
Other	85.8	65.1
Other current liabilities	$ 248.2	$ 222.9