Fair Value Measurements (Schedule of Carrying Values and Estimated Fair Values of Senior Notes) (Details) - CMLP - Crestwood Midstream Senior Notes - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Senior Notes, 2020
Debt Instrument [Line Items]
Carrying Amount	$ 340.6	$ 503.3
Fair Value	350.2	382.3
Senior Notes, 2022
Debt Instrument [Line Items]
Carrying Amount	429.3	588.4
Fair Value	447.3	437.4
Senior Notes, 2023
Debt Instrument [Line Items]
Carrying Amount	690.6	689.4
Debt Instrument, Fair Value Disclosure	$ 722.6	$ 491.8