Schedule of Details of Dividend Payments (Detail) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
	Jul. 02, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Equity [Abstract]
Record Date		Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Payment Date		Oct. 30, 2015	Jul. 31, 2015	Apr. 24, 2015	Jan. 30, 2015	Oct. 31, 2014	Jul. 25, 2014	Apr. 25, 2014	Jan. 31, 2014
Amount per Share		$ 0.29	$ 0.29	$ 0.28	$ 0.28	$ 0.28	$ 0.28	$ 0.27	$ 0.27
Total Amount		$ 43	$ 43	$ 42	$ 42	$ 43	$ 43	$ 42	$ 42
Maximum dividend allowed prior to merger	$ 0.29