This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 25

-Paragraph 23

-URI http://asc.fasb.org/extlink&oid=21917927&loc=d3e1043-128460

Name:	us-gaap_BusinessCombinationAcquisitionRelatedCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Charges and Credits - Summary of Merger and Integration Related Charges (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2013	Jun. 30, 2012
Restructuring Cost and Reserve [Line Items]
Charges, Pretax		$ 22			$ 37
Charges, Tax	19			19
Charges, Net	(683)	21	13		34
Merger - Related Integration Costs [Member]
Restructuring Cost and Reserve [Line Items]
Charges, Pretax		22	15		37
Merger-related transaction costs [Member]
Restructuring Cost and Reserve [Line Items]
Charges, Tax		$ 1	$ 2		$ 3