Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Accumulated other comprehensive income (loss) [Line Items]
Accumulated other comprehensive income (loss), balance at beginning of period	$ 68	$ (26)
Other comprehensive income (loss) before reclassifications	(24)	(36)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Accumulated other comprehensive income (loss), balance at end of period	44	(62)
Foreign currency translation adjustment
Accumulated other comprehensive income (loss) [Line Items]
Accumulated other comprehensive income (loss), balance at beginning of period	67	(26)
Other comprehensive income (loss) before reclassifications	(24)	(37)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Accumulated other comprehensive income (loss), balance at end of period	43	(63)
Unrealized gain on available-for-sale securities
Accumulated other comprehensive income (loss) [Line Items]
Accumulated other comprehensive income (loss), balance at beginning of period	1	0
Other comprehensive income (loss) before reclassifications	0	1
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Accumulated other comprehensive income (loss), balance at end of period	$ 1	$ 1