Stock Plans 9 (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Restricted Stock Awards (RSAs)
Summary of PSUs granted under long-term incentive plans
Shares	3.1	2.7	3.5
Weighted average grant date fair value (in dollars per share)	$ 28.97	$ 27.06	$ 26.21
Restricted Stock Units (RSUs)
Summary of PSUs granted under long-term incentive plans
Shares	0.8	0.7	0.9
Weighted average grant date fair value (in dollars per share)	$ 26.99	$ 25.45	$ 23.72
Fiscal Year 2014 Incentive Plan Year
Summary of PSUs granted under long-term incentive plans
Performance period (in years)	1 year
Fiscal Year 2014 Incentive Plan Year | Restricted Stock Awards (RSAs)
Summary of PSUs granted under long-term incentive plans
Shares	0.7
Weighted average grant date fair value (in dollars per share)	$ 29.91
Fiscal Year 2014 Incentive Plan Year | Restricted Stock Units (RSUs)
Summary of PSUs granted under long-term incentive plans
Shares	0.1
Weighted average grant date fair value (in dollars per share)	$ 28.92
Fiscal Year 2013 Incentive Plan Year
Summary of PSUs granted under long-term incentive plans
Performance period (in years)		1 year
Fiscal Year 2013 Incentive Plan Year | Restricted Stock Awards (RSAs)
Summary of PSUs granted under long-term incentive plans
Shares		0.4
Weighted average grant date fair value (in dollars per share)		$ 27.11
Fiscal Year 2013 Incentive Plan Year | Restricted Stock Units (RSUs)
Summary of PSUs granted under long-term incentive plans
Shares		0.1
Weighted average grant date fair value (in dollars per share)		$ 26.12
Fiscal Year 2012 Incentive Plan Year
Summary of PSUs granted under long-term incentive plans
Performance period (in years)			1 year
Fiscal Year 2012 Incentive Plan Year | Restricted Stock Awards (RSAs)
Summary of PSUs granted under long-term incentive plans
Shares			1.2
Weighted average grant date fair value (in dollars per share)			$ 26.39
Fiscal Year 2012 Incentive Plan Year | Restricted Stock Units (RSUs)
Summary of PSUs granted under long-term incentive plans
Shares			0.2
Weighted average grant date fair value (in dollars per share)			$ 25.40
Fiscal Year 2010 Incentive Plan Year
Summary of PSUs granted under long-term incentive plans
Performance period (in years)			3 years
Shares			0.2
Weighted average grant date fair value (in dollars per share)			$ 26.39
Fiscal Year 2014 Sales Retention Equity Program
Summary of PSUs granted under long-term incentive plans
Performance period (in years)	1 year
Fiscal Year 2014 Sales Retention Equity Program | Restricted Stock Awards (RSAs)
Summary of PSUs granted under long-term incentive plans
Shares	0.2
Weighted average grant date fair value (in dollars per share)	$ 28.69
Fiscal Year 2014 Sales Retention Equity Program | Restricted Stock Units (RSUs)
Summary of PSUs granted under long-term incentive plans
Shares	0.1
Weighted average grant date fair value (in dollars per share)	$ 25.73
Fiscal Year 2013 Sales Retention Equity Program
Summary of PSUs granted under long-term incentive plans
Performance period (in years)		1 year
Fiscal Year 2013 Sales Retention Equity Program | Restricted Stock Awards (RSAs)
Summary of PSUs granted under long-term incentive plans
Shares		0.2
Weighted average grant date fair value (in dollars per share)		$ 27.11
Fiscal Year 2013 Sales Retention Equity Program | Restricted Stock Units (RSUs)
Summary of PSUs granted under long-term incentive plans
Shares		0.1
Weighted average grant date fair value (in dollars per share)		$ 24.13
Fiscal Year 2012 Sales Retention Equity Program
Summary of PSUs granted under long-term incentive plans
Performance period (in years)			1 year
Fiscal Year 2012 Sales Retention Equity Program | Restricted Stock Awards (RSAs)
Summary of PSUs granted under long-term incentive plans
Shares			0.2
Weighted average grant date fair value (in dollars per share)			$ 26.39
Fiscal Year 2012 Sales Retention Equity Program | Restricted Stock Units (RSUs)
Summary of PSUs granted under long-term incentive plans
Shares			0.1
Weighted average grant date fair value (in dollars per share)			$ 23.41