Derivative Instruments and Hedging Activities (Changes in AOCI Related to Derivative Gains (Losses)) (Details) (USD $) In Millions, unless otherwise specified			3 Months Ended		6 Months Ended
	Dec. 31, 2011	Jun. 30, 2011	Dec. 31, 2011 Deferred Gain (Loss) On Hedging Activities [Member]	Dec. 31, 2010 Deferred Gain (Loss) On Hedging Activities [Member]	Dec. 31, 2011 Deferred Gain (Loss) On Hedging Activities [Member]	Dec. 31, 2010 Deferred Gain (Loss) On Hedging Activities [Member]
Balance of Accumulated Other Comprehensive Income (Loss) at beginning of period	$ (563)	$ 176	$ 30	$ 56	$ 29	$ 30
Unrealized gains			16	135	22	247
Losses (gains) reclassified to earnings			(16)	(154)	(19)	(225)
Tax effect			0	6	(2)	(9)
Balance of Accumulated Other Comprehensive Income (Loss) at End of period	$ (563)	$ 176	$ 30	$ 43	$ 30	$ 43