Employee Incentive Plans (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Compensation Costs And Related Tax Benefits Table Details [Abstract]
Compensation costs	$ 98	$ 61	$ 49
Tax benefits	26	14	12
Number of shares of common stock available for award	8,400,000	11,700,000	7,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding - January 1	9,581,000	12,093,000	13,751,000
Options Granted	3,446,000	1,546,000	1,846,000
Options Exercised	(3,740,000)	(3,480,000)	(2,565,000)
Options Expired or canceled	(336,000)	(578,000)	(939,000)
Options outstanding - December 31	8,951,000	9,581,000	12,093,000
Options Exercisable - Number (in thousands)	5,731,000	6,147,000	7,656,000
Share Based Compensation Arrangement By Share Based Payment Award, Options Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted Average Exercise Price - Options Outstanding - January 1	$ 33.92	$ 31.10	$ 29.34
Weighted Average Exercise Price - Options Granted	$ 28.29	$ 42.36	$ 34.64
Weighted Average Exercise Price - Options Exercised	$ 22.72	$ 27.93	$ 24.31
Weighted Average Exercise Price - Options Expired or canceled	$ 37.85	$ 33.61	$ 30.86
Weighted Average Exercise Price - Options Outstanding - December 31	$ 36.29	$ 33.92	$ 31.10
Options Exercisable - Weighted Average Exercise Price	$ 34.93	$ 34.94	$ 34.42
Information For Stock Options Exercised Details [Abstract]
Intrinsic value of options exercised	95	53	30
Cash received for options exercised	85	97	62
Excess tax benefits realized from options exercised	15	10	5
Information for Outstanding Common Stock Options [Abstract]
Options Outstanding - Number (in thousands)	8,951,000	9,581,000	12,093,000
Options Outstanding - Total intrinsic value	154
Options Outstanding - Weighted Average Exercise Price	$ 36.29	$ 33.92	$ 31.10
Options Outstanding - Weighted average remaining contractual life	6.3
Options Exercisable - Number (in thousands)	5,731,000	6,147,000	7,656,000
Options Exercisable - Total Intrinsic Value	106
Options Exercisable - Weighted Average Exercise Price	$ 34.93	$ 34.94	$ 34.42
Options Exercisable - Weighted Average Remaining Contractual Life	5.1
Assumptions For Fair Value of Options Granted Details [Abstract]
Dividend Yield	0.10%	0.10%	0.10%
Expected Volatility	40.00%	40.00%	40.00%
Risk-free Interest Rate	0.80%	1.70%	1.90%
Expected Option Life	4.5	4	4
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Compensation expense related to non-vested share-based awards	20
Period in which compensation expense will be recognized	2
Stock option vesting period	one to five years
Stock option expiration period	no later than 10 years from grant date
Weighted average fair value of options granted under employee incentive plans	$ 14.99	$ 13.96	$ 11.56
Stock Options [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Stock option vesting period	1 year
Stock Options [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Stock option vesting period	5 years
Restricted Stock Grants And Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Nonvested, Roll Forward
Outstanding - January 1	4,246,000	4,306,000	4,113,000
Awarded	1,563,000	945,000	1,155,000
Vested	(1,485,000)	(564,000)	(541,000)
Forfeited	(260,000)	(441,000)	(421,000)
Outstanding - December 31	4,064,000	4,246,000	4,306,000
Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Outstanding - January 1	$ 28.88	$ 27.70	$ 27.65
Awarded	$ 44.37	$ 42.62	$ 34.63
Vested	$ 27.60	$ 42.79	$ 40.87
Forfeited	$ 33.61	$ 28.99	$ 29.28
Outstanding - December 31	$ 35.00	$ 28.88	$ 27.70
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Compensation expense related to non-vested share-based awards	69
Period in which compensation expense will be recognized	3
Fair value of vested restricted stock	66	24	18
Number of employees holding share based payment awards at the reporting date.	3,200
Strategic Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Nonvested, Roll Forward
Outstanding - January 1	834,000	430,000	0
Awarded	842,000	529,000	480,000
Forfeited	(76,000)	(125,000)	(50,000)
Outstanding - December 31	1,600,000	834,000	430,000
Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Outstanding - January 1	$ 39.45	$ 34.73	$ 0
Awarded	$ 44.49	$ 42.92	$ 34.73
Forfeited	$ 43.39	$ 37.92	$ 34.65
Outstanding - December 31	$ 41.92	$ 39.45	$ 34.73
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Compensation expense related to non-vested share-based awards	$ 26
Period in which compensation expense will be recognized	2
Number of employees holding share based payment awards at the reporting date.	955
Strategic Performance Shares Subject to Market Conditions	50.00%
Strategic Performance Shares Subject to Performance Conditions	50.00%
Strategic Performance Shares [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Percent of original grant awarded at end of performance period	0.00%
Strategic Performance Shares [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Percent of original grant awarded at end of performance period	200.00%

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

+ References

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- Definition

The weighted average period between the balance sheet date and expiration for all vested portions of options outstanding and currently exercisable (or convertible) under the plan, which may be expressed in a decimal value for number of years.

+ References

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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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- Definition

The weighted average price at which option holders acquired shares when converting their stock options into shares under the plan during the reporting period.

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- Definition

For presentations that combine terminations, 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 or that expired.

+ References

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- Definition

The combined weighted average exercise price associated with stock options during the period that have either lapsed or been forfeited.

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- Definition

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

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The weighted average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on stock options awarded under the plan during the reporting 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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- Definition

The total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices pertaining to options outstanding under the plan as of the balance sheet date.

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(a)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Paragraph A240

-Subparagraph b(1)(b)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The weighted average price as of the beginning of the year at which grantees can acquire the shares reserved for issuance under the stock option plan.

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- Definition

The weighted average period between the balance sheet date and expiration for all awards outstanding under the plan, which may be expressed in a decimal value for number of years.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Paragraph 2

-Subparagraph (e)(1)

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-Topic 718

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Number of share options (or share units) exercised during the current period.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

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-Publisher FASB

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-Name Regulation S-X (SX)

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-Section 02

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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-Section S99

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-Subparagraph (SX 210.3-04)

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