Employee Benefit Plans (Schedule Of Fair Value Of Plan Assets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Jun. 30, 2012	Jun. 30, 2011
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	$ 2,174	$ 2,236	$ 2,134
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	851	895	782
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	1,323	1,341	1,352
Common stock - U.S. companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	182	184	180
Common stock - U.S. companies [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	182	184	180
Common stock - International companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	1	2	5
Common stock - International companies [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	1	2	5
Equity mutual funds - Emerging markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	81	77	70
Equity mutual funds - Emerging markets [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	81	77	70
Equity mutual funds - International [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	110	109	99
Equity mutual funds - International [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	110	109	99
Equity mutual funds - Large cap U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	386	415	378
Equity mutual funds - Large cap U.S. [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	386	415	378
Equity mutual funds - Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	1		1
Equity mutual funds - Other [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	1		1
Common collective trust funds - International equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	406	372	341
Common collective trust funds - International equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	406	372	341
Common collective trust funds - Large cap U.S. equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	17	16	24
Common collective trust funds - Large cap U.S. equity [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	17	16	24
Common collective trust funds - Fixed income [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	373	409	444
Common collective trust funds - Fixed income [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	373	409	444
Common collective trust funds - Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	47	59	60
Common collective trust funds - Other [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	47	59	60
Debt instruments - Corporate bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	437	447	442
Debt instruments - Corporate bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	437	447	442
Debt instruments - U.S. Treasury instruments [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	90	108	49
Debt instruments - U.S. Treasury instruments [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	90	108	49
Debt instruments - U.S. government agency, state and local government bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	39	33	35
Debt instruments - U.S. government agency, state and local government bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	39	33	35
Other Debt Instruments [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	4	5	6
Other Debt Instruments [Member] | Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets at fair value	$ 4	$ 5	$ 6