Fair Value Measurements (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Deferred Compensation Liability [Abstract]
Deferred compensation obligations	$ 3.0	$ 2.6
Trading securities	3.0us-gaap_TradingSecurities	2.6us-gaap_TradingSecurities
Assets Held For Sale [Abstract]
Carrying value of assets held-for-sale	3.2	11.6
U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	217.0	213.7
Money Market Investments [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	8.1	11.3
Common Stocks [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	42.7	42.2
Corporate Bonds [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	23.5	21.3
Pooled Equity Funds [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	80.4	80.8
Pooled Fixed-income Funds [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	15.5	14.1
US Government and Agency Securities [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	39.8	37.0
Other [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	7.0	7.0
Level 1 [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	125.7	124.7
Level 1 [Member] \| Money Market Investments [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	0	0
Level 1 [Member] \| Common Stocks [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	40.5	40.1
Level 1 [Member] \| Corporate Bonds [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	0	0
Level 1 [Member] \| Pooled Equity Funds [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	69.0	68.9
Level 1 [Member] \| Pooled Fixed-income Funds [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	15.5	14.1
Level 1 [Member] \| US Government and Agency Securities [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	0	0
Level 1 [Member] \| Other [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	0.7	1.6
Level 2 [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	91.3	89.0
Level 2 [Member] \| Money Market Investments [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	8.1	11.3
Level 2 [Member] \| Common Stocks [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	2.2	2.1
Level 2 [Member] \| Corporate Bonds [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	23.5	21.3
Level 2 [Member] \| Pooled Equity Funds [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	11.4	11.9
Level 2 [Member] \| Pooled Fixed-income Funds [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	0	0
Level 2 [Member] \| US Government and Agency Securities [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	39.8	37.0
Level 2 [Member] \| Other [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	6.3	5.4
Level 3 [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	0	0
Level 3 [Member] \| Money Market Investments [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	0	0
Level 3 [Member] \| Common Stocks [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	0	0
Level 3 [Member] \| Corporate Bonds [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	0	0
Level 3 [Member] \| Pooled Equity Funds [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	0	0
Level 3 [Member] \| Pooled Fixed-income Funds [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	0	0
Level 3 [Member] \| US Government and Agency Securities [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	0	0
Level 3 [Member] \| Other [Member] \| U.S. Pension Plans [Member]
U.S. pension plan assets [Abstract]
Fair value of plan assets	$ 0	$ 0

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