Preferred and Common Stockholder's Equity - Reconciliation of Denominators of Basic and Diluted Earnings Per Share Computations (Detail) - shares shares in Millions	3 Months Ended			6 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Weighted-average shares outstanding used to compute basic EPS	74.2	69.3	[1]	73.6	68.9	[1]
Effect of dilutive shares	2.3	2.6		3.3	2.3
Weighted-average shares outstanding and dilutive securities used to compute diluted EPS	76.5	71.9	[1]	76.9	71.2	[1]

[1] Amounts adjusted due to the adoption of Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606). See Note 1 to the financial statements contained in Part I, Item 1 of this report for additional information.