Equity - Additional Information (Detail) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended			6 Months Ended			30 Months Ended	1 Months Ended	6 Months Ended	1 Months Ended
	Jun. 30, 2014	Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013	Jun. 30, 2014	Jul. 31, 2014 Scenario, Forecast	Jun. 30, 2013 Accelerated Share Repurchase Program November 2012	Jul. 31, 2014 Subsequent Event Share Repurchase Authorization July 2014	Jul. 30, 2014 Subsequent Event Share Repurchase Authorization July 2014
Equity, Class of Treasury Stock [Line Items]
Stock repurchase plan authorized amount	$ 6,000,000,000			$ 6,000,000,000			$ 6,000,000,000				$ 2,000,000,000
Cash paid for shares repurchased	459,000,000	882,000,000		1,148,000,000		1,313,000,000	5,290,000,000	12,000,000
Stock repurchase plan remaining authorized amount	$ 709,000,000			$ 709,000,000			$ 709,000,000
Ending date of share repurchase authorization				Sep. 30, 2015						Jul. 30, 2016
Number of shares repurchased	5	11	[1]	13	[1]	17	78		1
Effective average cost per delivered share	$ 88.14	$ 80.31		$ 87.82		$ 80.54	$ 67.65

[1] The six months ended June 30, 2013 includes one million shares received under the November 2012 accelerated share repurchase program, which were paid for in 2012.