Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Jan. 31, 2015	Sep. 30, 2007
Class Of Stock [Line Items]
Repurchase authorization, shares				5,000,000	10,000,000
Cash dividends paid to common stockholders		$ 47	$ 42
Cash dividend paid per share		$ 0.74	$ 0.66
Noncontrolling interest dividends declared		$ 16	$ 22
Dividends paid to noncontrolling interests	$ 6	$ 16	$ 16
2007 Share Repurchase Authorization [Member]
Class Of Stock [Line Items]
Common stock shares repurchased			925,700
January 2015 Share Repurchase Authorization [Member]
Class Of Stock [Line Items]
Common stock shares repurchased		1,875,676
Shares remaining available for repurchase under the current authorization		3,124,324