Retirement Income And Health Care Benefit Plans (Components Of Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010
Retirement Income And Health Care Benefit Plans [Abstract]
Service cost		$ 4	$ 1	$ 7
Interest cost	7	7	14	14
Expected return on plan assets	(7)	(8)	(15)	(16)
Amortization of unrecognized items	2	4	4	8
Total	$ 2	$ 7	$ 4	$ 13