Consolidated Statement of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 46us-gaap_NetIncomeLoss	$ 2,856us-gaap_NetIncomeLoss	$ 2,609us-gaap_NetIncomeLoss
Other comprehensive income (loss), net of reclassification adjustments:
Foreign currency translation gain (loss)	(323)	208	337
Unrealized gains (losses) on investments, net	108	234	99
Tax (expense) benefit on unrealized gains (losses) on investments, net	(37)	(93)	(6)
Unrealized gains (losses) on hedging activities, net	274	(51)	(127)
Tax (expense) benefit on unrealized gains (losses) on hedging activities, net	(7)	2	4
Other comprehensive income (loss), net of tax	15	300	307
Comprehensive income	$ 61us-gaap_ComprehensiveIncomeNetOfTax	$ 3,156us-gaap_ComprehensiveIncomeNetOfTax	$ 2,916us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount before tax, after reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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