Share Repurchase Program and Dividend - Additional Information (Detail) - USD ($)			6 Months Ended	12 Months Ended
	Jul. 14, 2015	Feb. 10, 2015	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount			$ 7,000,000,000	$ 7,000,000,000
Stock repurchase program, remaining authorized amount			$ 2,400,000,000	$ 2,400,000,000
Stock repurchased (in shares)				85,141,691	23,406,472
Aggregate stock repurchase price				$ 3,586,000,000	$ 1,000,000,000
Total cash payment for dividends				$ 278,000,000	$ 144,000,000
Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Stock repurchased (in shares)	100,000	100,000	108,500,000	85,100,000	23,400,000
Aggregate stock repurchase price	$ 2,000,000	$ 4,000,000	$ 4,600,000,000	$ 1,000,000	$ 1,000,000,000
Average cost per share			$ 42.23	$ 42.09	$ 42.72