Accounting for Share-Based Compensation 4 (Details) - $ / shares shares in Millions		3 Months Ended					6 Months Ended
		Sep. 30, 2016		Jun. 30, 2016	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Restricted Stock Awards (RSAs)
Summary of PSUs granted under long-term incentive plans
Shares		0.0	[1]		0.1		2.9	2.8
Weighted average grant date fair value (in dollars per share)	[2]	$ 34.31			$ 29.86		$ 31.55	$ 30.64
Restricted Stock Units (RSUs)
Summary of PSUs granted under long-term incentive plans
Shares		0.0	[1]		0.1		1.0	0.9
Weighted average grant date fair value (in dollars per share)	[3]	$ 31.82			$ 27.72		$ 30.16	$ 28.72
Fiscal Year 2016 Incentive Plans | 1-year PSUs under Incentive Plans
Summary of PSUs granted under long-term incentive plans
Performance period (in years)				1 year
Fiscal Year 2016 Incentive Plans | 1-year PSUs under Incentive Plans | Restricted Stock Awards (RSAs)
Summary of PSUs granted under long-term incentive plans
Shares				0.6
Weighted average grant date fair value (in dollars per share)				$ 31.53
Fiscal Year 2016 Incentive Plans | 1-year PSUs under Incentive Plans | 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)				$ 30.53
Fiscal Year 2016 Incentive Plans | 1-year PSUs under Sales Retention Equity Programs
Summary of PSUs granted under long-term incentive plans
Performance period (in years)				1 year
Fiscal Year 2016 Incentive Plans | 1-year PSUs under Sales Retention Equity Programs | Restricted Stock Awards (RSAs)
Summary of PSUs granted under long-term incentive plans
Shares				0.3
Weighted average grant date fair value (in dollars per share)				$ 31.53
Fiscal Year 2016 Incentive Plans | 1-year PSUs under Sales Retention Equity Programs | 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)				$ 28.52
Fiscal Year 2015 Incentive Plans | 1-year PSUs under Incentive Plans
Summary of PSUs granted under long-term incentive plans
Performance period (in years)						1 year
Fiscal Year 2015 Incentive Plans | 1-year PSUs under Incentive Plans | Restricted Stock Awards (RSAs)
Summary of PSUs granted under long-term incentive plans
Shares						0.5
Weighted average grant date fair value (in dollars per share)						$ 31.41
Fiscal Year 2015 Incentive Plans | 1-year PSUs under Incentive Plans | 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)						$ 30.42
Fiscal Year 2015 Incentive Plans | 1-year PSUs under Sales Retention Equity Programs
Summary of PSUs granted under long-term incentive plans
Performance period (in years)						1 year
Fiscal Year 2015 Incentive Plans | 1-year PSUs under Sales Retention Equity Programs | 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)						$ 30.45
Fiscal Year 2015 Incentive Plans | 1-year PSUs under Sales Retention Equity Programs | 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)						$ 27.50
Fiscal Year 2014 Incentive Plans | 3-year PSUs under Incentive Plans
Summary of PSUs granted under long-term incentive plans
Performance period (in years)				3 years
Shares				0.3
Weighted average grant date fair value (in dollars per share)				$ 31.53
Fiscal Year 2013 Incentive Plans | 3-year PSUs under Incentive Plans
Summary of PSUs granted under long-term incentive plans
Performance period (in years)						3 years
Shares						0.1
Weighted average grant date fair value (in dollars per share)						$ 31.41

[1] Less than 0.1 million.

[2] The fair value is based on the quoted market value of the Company’s common stock on the grant date.

[3] The fair value is based on the quoted market value of the Company’s common stock on the grant date reduced by the present value of dividends expected to be paid on the Company’s common stock prior to vesting of the RSUs, which is calculated using a risk-free interest rate.