Capital Actions (Capital Actions) (Detail) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015
Capital Actions [Line Items]
Shares acquired for treasury	$ 265	$ 335
December 10, 2015 ASR \| March 2014 Repurchase Program
Capital Actions [Line Items]
Repurchase date	Dec. 14, 2015
Shares acquired for treasury	$ 215
Shares repurchased on repurchase date	9,248,482
Shares received from forward contract settlement	1,782,477
Total shares repurchased	11,030,959
Settlement date	Jan. 14, 2016
March 2, 2016 ASR \| March 2014 Repurchase Program
Capital Actions [Line Items]
Repurchase date	Mar. 04, 2016
Shares acquired for treasury	$ 240
Shares repurchased on repurchase date	12,623,762
Shares received from forward contract settlement	1,868,379
Total shares repurchased	14,492,141
Settlement date	Apr. 11, 2016
June 15, 2016 Open Market Share Repurchase \| March 2014 Repurchase Program
Capital Actions [Line Items]
Shares acquired for treasury	$ 26
Shares repurchased on repurchase date	1,436,100
Total shares repurchased	1,436,100
Settlement date	Jun. 20, 2016

Common stock repurchased in an ASR transaction

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- Definition

Initial redemption date for share repurchase transaction

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Settlement date of the forward contract indexed to issuer's equity, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 50
-Paragraph 5
-Subparagraph (a)(4)
-URI http://asc.fasb.org/extlink&oid=6445032&loc=d3e90205-114008

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- Definition

Additional shared included in the calculation of diluted EPS as a result of the potentially dilutive effect of equity forward arrangements using the reverse treasury stock method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
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- Definition

Number of stock bought back by the entity at the exercise price or redemption price.

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- Definition

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

+ References

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-Name Accounting Standards Codification
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