Condensed Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Net income	$ 222	$ 201
Other comprehensive income (loss), net of tax:
Change in unrealized gains and losses on available-for-sale securities	(1)	(42)
Change in unrealized losses on derivative instruments	(2)	0
Reclassification adjustment for realized losses on derivative instruments	2	1
Foreign currency translation adjustments	(12)	(17)
Total other comprehensive income (loss), net of tax	(13)	(58)
Total comprehensive income	$ 209	$ 143