Accounting for Share-Based Compensation 5 (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Capitalized share-based compensation costs	$ 0	$ 0			$ 0	$ 0
Stock options issued					1.0	1.1
Computation of expected life, Simplified method					The Company’s computation of expected life was determined based on the simplified method (the average of the vesting period and option term).
Employee Stock Purchase Plan (ESPP)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares issued under ESPP			0.1	0.1
Share price issued under ESPP (in dollars per share)			$ 31.62	$ 32.75
Number of shares available for future issuances under ESPP	28.8		28.8		28.8