Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2010
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at beginning of period	$ (907)	$ 176	$ 176
Net of tax amount	465	(739)	(1,089)	1,075	(544)
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	(450)		(907)	176
Foreign Currency Translation Adjustment [Member]
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at beginning of period	(176)	509	509
Net realized gains (losses)	363		(745)
Tax effect	(51)		60
Net of tax amount	312		(685)
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	136		(176)
Deferred Gain (Loss) On Hedging Activities [Member]
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at beginning of period	50	29	29
Net realized gains (losses)	(72)		36
Tax effect	26		(15)
Net of tax amount	(46)		21
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	4		50
Pension Liability Adjustment [Member]
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at beginning of period	(782)	(419)	(419)
Net realized gains (losses)	292		(565)
Tax effect	(100)		202
Net of tax amount	192		(363)
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	(590)		(782)
Unrealized Gain (Loss) On Investments [Member]
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at beginning of period	1	57	57
Net realized gains (losses)	(1)		(90)
Tax effect			34
Net of tax amount	(1)		(56)
Balance of Accumulated Other Comprehensive Income (Loss) at End of period			1
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated other comprehensive income (loss)
Balance of Accumulated Other Comprehensive Income (Loss) at beginning of period	(907)	176	176
Net realized gains (losses)	582		(1,364)
Tax effect	(125)		281
Net of tax amount	457		(1,083)	1,075	(544)
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	$ (450)		$ (907)	$ 176