Segment Information - Depreciation Expense, by Segment (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation Of Depreciation By Segment [Line Items]
Depreciation expense	$ 2,460	$ 1,653	$ 1,034
North America
Reconciliation Of Depreciation By Segment [Line Items]
Depreciation expense	1,863	1,229	795
International
Reconciliation Of Depreciation By Segment [Line Items]
Depreciation expense	$ 597	$ 424	$ 239

The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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