Accounting for Share-Based Compensation 4 (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Restricted Stock Awards (RSAs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted	0	[1]	0	[1]	2.7		3.6
Weighted average grant date fair value	$ 30.39	[2]	$ 25.54	[2]	$ 27.01	[2]	$ 26.23	[2]
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted	0	[1]	0	[1]	0.8		0.7
Weighted average grant date fair value	$ 30.13	[3]	$ 23.63	[3]	$ 25.37	[3]	$ 24.29	[3]
1-Year PSUs for Fiscal Year 2013 Incentive Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period					1 year
1-Year PSUs for Fiscal Year 2013 Incentive Plans [Member] | Restricted Stock Awards (RSAs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted					0.4
Weighted average grant date fair value					$ 27.11
1-Year PSUs for Fiscal Year 2013 Incentive Plans [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted					0.1
Weighted average grant date fair value					$ 26.12
1-Year PSUs for Fiscal Year 2012 Incentive Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period							1 year
1-Year PSUs for Fiscal Year 2012 Incentive Plans [Member] | Restricted Stock Awards (RSAs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted							1.2
Weighted average grant date fair value							$ 26.39
1-Year PSUs for Fiscal Year 2012 Incentive Plans [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted							0.2
Weighted average grant date fair value							$ 25.40
3-Year PSUs for Fiscal Year 2010 Incentive Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period							3 years
Number of shares granted							0.2
Weighted average grant date fair value							$ 26.39
1-Year PSUs for Fiscal Year 2013 Sales Retention Equity Programs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period					1 year
1-Year PSUs for Fiscal Year 2013 Sales Retention Equity Programs [Member] | Restricted Stock Awards (RSAs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted					0.2
Weighted average grant date fair value					$ 27.11
1-Year PSUs for Fiscal Year 2013 Sales Retention Equity Programs [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted					0.1
Weighted average grant date fair value					$ 24.13
1-Year PSUs for Fiscal Year 2012 Sales Retention Equity Programs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period							1 year
1-Year PSUs for Fiscal Year 2012 Sales Retention Equity Programs [Member] | Restricted Stock Awards (RSAs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted							0.2
Weighted average grant date fair value							$ 26.39
1-Year PSUs for Fiscal Year 2012 Sales Retention Equity Programs [Member] | Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares granted							0.1
Weighted average grant date fair value							$ 23.41

[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.