Share Repurchase Programs and Dividends - Share Repurchase Programs (Detail) $ / shares in Units, shares in Millions	3 Months Ended	33 Months Ended
	Mar. 31, 2017 USD ($) $ / shares shares	Mar. 31, 2017 USD ($) $ / shares shares
Class of Stock Disclosures [Abstract]
Stock repurchase programs, authorized amount	$ 11,000,000,000	$ 11,000,000,000
Stock repurchase programs, remaining authorized amount	$ 1,500,000,000	$ 1,500,000,000
Number of share repurchase programs authorized		6
Stock repurchased (in shares) | shares	11.7	240.0
Aggregate stock repurchase price	$ 512,000,000	$ 9,500,000,000
Average cost per share (in dollars per share) | $ / shares	$ 43.81	$ 39.62