Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

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-Section S99

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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-Number 210

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold or consumed after one year or beyond the normal operating cycle, if longer.

+ References

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

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The net result for the period of deducting operating expenses from operating revenues.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

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

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Business Segments, Geographic Information and Major Customers (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Information concerning our revenue, income from operations, non-current and total assets, as segregated between the Americas, EMEA (Europe, Middle East, and Africa) and the Asia/Pacific regions
Revenues	$ 9,779,555us-gaap_Revenues	$ 11,713,463us-gaap_Revenues	$ 11,342,475us-gaap_Revenues	$ 10,550,896us-gaap_Revenues	$ 10,404,653us-gaap_Revenues	$ 10,493,661us-gaap_Revenues	$ 10,479,604us-gaap_Revenues	$ 10,184,029us-gaap_Revenues	$ 43,386,389us-gaap_Revenues	$ 41,561,947us-gaap_Revenues	$ 38,945,338us-gaap_Revenues
Income from operations:
Income from operations									269,148us-gaap_OperatingIncomeLoss	264,358us-gaap_OperatingIncomeLoss	257,023us-gaap_OperatingIncomeLoss
Non-current assets:
Non-current assets	1,205,137us-gaap_AssetsNoncurrent				923,776us-gaap_AssetsNoncurrent				1,205,137us-gaap_AssetsNoncurrent	923,776us-gaap_AssetsNoncurrent
Total assets:
Total assets	4,879,980us-gaap_Assets				4,739,277us-gaap_Assets				4,879,980us-gaap_Assets	4,739,277us-gaap_Assets
United States
Information concerning our revenue, income from operations, non-current and total assets, as segregated between the Americas, EMEA (Europe, Middle East, and Africa) and the Asia/Pacific regions
Revenues									21,514,304	21,149,175	20,216,891
Income from operations:
Income from operations									52,226	49,874	67,041
Non-current assets:
Non-current assets	549,521				560,623				549,521	560,623
Total assets:
Total assets	1,909,541				2,239,479				1,909,541	2,239,479
EMEA
Information concerning our revenue, income from operations, non-current and total assets, as segregated between the Americas, EMEA (Europe, Middle East, and Africa) and the Asia/Pacific regions
Revenues									8,612,751	7,017,479	7,247,754
Income from operations:
Income from operations									121,660	109,650	82,964
Non-current assets:
Non-current assets	591,481				319,339				591,481	319,339
Total assets:
Total assets	1,695,200				1,347,020				1,695,200	1,347,020
United Kingdom
Information concerning our revenue, income from operations, non-current and total assets, as segregated between the Americas, EMEA (Europe, Middle East, and Africa) and the Asia/Pacific regions
Revenues									6,200,000	5,000,000	5,200,000
Asia/ Pacific
Information concerning our revenue, income from operations, non-current and total assets, as segregated between the Americas, EMEA (Europe, Middle East, and Africa) and the Asia/Pacific regions
Revenues									9,844,682	10,215,412	8,404,324
Income from operations:
Income from operations									74,737	70,547	71,054
Non-current assets:
Non-current assets	12,351				2,050				12,351	2,050
Total assets:
Total assets	922,705				817,887				922,705	817,887
Singapore
Information concerning our revenue, income from operations, non-current and total assets, as segregated between the Americas, EMEA (Europe, Middle East, and Africa) and the Asia/Pacific regions
Revenues									9,700,000	10,100,000	8,400,000
Americas, excluding United States
Information concerning our revenue, income from operations, non-current and total assets, as segregated between the Americas, EMEA (Europe, Middle East, and Africa) and the Asia/Pacific regions
Revenues									3,414,652	3,179,881	3,076,369
Income from operations:
Income from operations									20,525	34,287	35,964
Non-current assets:
Non-current assets	51,784				41,764				51,784	41,764
Total assets:
Total assets	$ 352,534				$ 334,891				$ 352,534	$ 334,891