Accumulated Other Comprehensive Income (Loss) (Details) (USD $)	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Accumulated other comprehensive income (loss) [Line Items]
Accumulated other comprehensive income (loss), balance at beginning of period	$ (26,000,000)	$ (72,000,000)
Other comprehensive income (loss) before reclassifications	(36,000,000)	(52,000,000)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Accumulated other comprehensive income (loss), balance at end of period	(62,000,000)	(124,000,000)
Foreign currency translation adjustment
Accumulated other comprehensive income (loss) [Line Items]
Accumulated other comprehensive income (loss), balance at beginning of period	(26,000,000)	(72,000,000)
Other comprehensive income (loss) before reclassifications	(37,000,000)	(53,000,000)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Accumulated other comprehensive income (loss), balance at end of period	(63,000,000)	(125,000,000)
Unrealized gain on available-for-sale securities
Accumulated other comprehensive income (loss) [Line Items]
Accumulated other comprehensive income (loss), balance at beginning of period	0	0
Other comprehensive income (loss) before reclassifications	1,000,000	1,000,000
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Accumulated other comprehensive income (loss), balance at end of period	$ 1,000,000	$ 1,000,000