Retirement Income And Health Care Benefit Plans (Components Of Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011
Retirement Income And Health Care Benefit Plans [Abstract]
Service cost	$ 1	$ 2	$ 2	$ 9
Interest cost	8	8	22	22
Expected return on plan assets	(8)	(9)	(23)	(25)
Amortization of unrecognized items	2	5	6	13
Total	$ 3	$ 6	$ 7	$ 19