Quarterly Financial Data (Unaudited) Quarterly Financial Data (Unaudited) - Narrative (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 12 Months Ended
Sep. 30, 2014
Mar. 31, 2014
Mar. 31, 2013
Dec. 31, 2012
Asset Impairment Charges $ 47.9 $ 38.2 $ 85.3 $ 22.8