Business Acquisitions (Details) (USD $)	3 Months Ended
Mar. 31, 2015 Business	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill	$ 5,088,040,000us-gaap_Goodwill	$ 4,710,691,000us-gaap_Goodwill
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Number of business acquired	3
Cost of Acquired Entity Purchase Price	590,000,000
Intangible Assets Other than Goodwill	212,000,000
Goodwill	418,000,000
Cost of Acquired Entity Transaction Costs	1,800,000
Finite lived intangible assets	192,000,000
Indefinite lived intangible assets	20,000,000
Weighted average useful life	17 years
Series of Individually Immaterial Business Acquisitions [Member] \| Customer Relationships [Member]
Business Acquisition [Line Items]
Finite lived intangible assets	153,000,000
Weighted average useful life	19 years
Series of Individually Immaterial Business Acquisitions [Member] \| Software [Member]
Business Acquisition [Line Items]
Finite lived intangible assets	$ 39,000,000
Weighted average useful life	6 years

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (a)(3)

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- Definition

Amount of direct costs of the business combination including legal, accounting, and other costs incurred to consummate the business acquisition.

+ References

No definition available.

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- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 30

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477

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- Definition

Amount of assets, excluding financial assets and goodwill, that lack physical substance, having a projected indefinite period of benefit, acquired at the acquisition date.

+ References

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- Definition

Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

+ References

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- Definition

The amount of identifiable intangible assets recognized as of the acquisition date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 20

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- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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- Definition

The number of businesses acquired by the entity during the period.

+ References

No definition available.

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