Basic and Diluted Earnings Per Share - Additional Information (Detail) shares in Millions		3 Months Ended
	Mar. 19, 2015	Dec. 31, 2015 shares	Dec. 31, 2014 shares
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Common stock equivalents included in the computation of diluted shares outstanding		5	5
Common stock equivalents excluded from computation of average dilutive shares outstanding		1	2
Class A common stock
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Stock split, conversion ratio	4
Class B common stock
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Weighted-average as-converted common stock used in income allocation		405	405
Class C common stock
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Weighted-average as-converted common stock used in income allocation		78	88