Common Stock Repurchase Program (Details) - USD ($)	5 Months Ended	6 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Oct. 01, 2016	Apr. 01, 2017	May 16, 2016
Accelerated Share Repurchases [Line Items]
Stock Repurchased and Retired During Period, Value		$ 237,500,000	$ 200,100,000
Stock Repurchased and Retired During Period, Shares		3,700,000	4,100,000
Treasury shares	0	0		0
Repurchase Program Two Thousand Sixteen [Member] [Domain]
Accelerated Share Repurchases [Line Items]
Stock Repurchase Program, Authorized Amount					$ 1,000,000,000
Stock Repurchased During Period, Value	$ 555,400,000.0
Total amount available for future repurchases	$ 444,600,000	$ 444,600,000