v2.4.0.6

Employee Benefit Plans - Summary of Stock Option Activity for Three Years Ended December 31, 2011 (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option Outstanding at the beginning of year	32,611,874	36,433,473	36,615,753
Stock option, granted	1,907,000	3,040,500	3,311,200
Stock option, exercised	(10,022,685)	(6,401,483)	(2,919,118)
Stock option, forfeited	(82,434)	(255,889)	(332,941)
Stock option, expired or canceled	(41,704)	(204,727)	(241,421)
Stock option Outstanding at the end of year	24,372,051	32,611,874	36,433,473
Weighted-Average Exercise Price at the beginning of year	$ 39.54	$ 37.13	$ 35.65
Stock option, vested	22,214,254
Weighted-Average Exercise Price, granted	$ 70.13	$ 48.39	$ 45.47
Stock option Outstanding at the end of year	19,666,959
Weighted-Average Exercise Price, exercised	$ 30.08	$ 29.08	$ 24.10
Weighted-Average Exercise Price, forfeited	$ 62.26	$ 48.42	$ 52.04
Weighted-Average Exercise Price, expired or canceled	$ 51.60	$ 58.94	$ 63.49
Weighted-Average Exercise Price at the end of year	$ 45.73	$ 39.54	$ 37.13
Weighted-Average Exercise Price, vested	$ 44.49
Weighted-Average Exercise Price at the end of year	$ 43.19
Weighted-Average Grant-Date Fair Value, Granted	$ 16.70	$ 11.70	$ 11.18
Aggregate Intrinsic Value, Exercised	$ 416	$ 183	$ 67
Aggregate Intrinsic Value, Vested	611
Aggregate Intrinsic Value, Exercisable	$ 564

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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The total accumulated difference between fair values of underlying shares on dates of exercise and exercise price on options which were exercised (or share units converted) into shares during the reporting period under the plan.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Net number of share options (or share units) granted during the period.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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The number of exercisable share options (fully vested and expected to vest) that may be converted as of the balance sheet date.

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