Retirement Benefits Defined Contribution Savings Plans (Details) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | ||
---|---|---|---|
Mar. 31, 2014
|
Mar. 31, 2013
|
Mar. 31, 2012
|
|
Compensation and Retirement Disclosure [Abstract] | |||
Defined Contribution Plan, Cost Recognized | $ 15.6 | $ 14.2 | $ 11.0 |