Employee Benefit Plans (Narrative) (Details) (USD $) Share data in Millions, unless otherwise specified	6 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2012	Jun. 30, 2011
Defined Benefit Plan Disclosure [Line Items]
Percentage of non-matching employer's contribution to eligible participants (as a percent)	1.00%
Employer's Common stock held under 401 (k) plan (in shares)	15
Market value of employer's Common stock held under 401 (k) plan	$ 412,000,000
Cash dividend received on employer's Common stock held under 401 (k) plan	5,000,000
U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension plan voluntary lump-sum payments	134,000,000
Reduction in global pension benefit obligation as a result of voluntary lump-sum payments	174,000,000
Improvement in pension underfunding as a result of pension plan voluntary lump-sum payments	40,000,000
Non-cash charge resulting from expensing unrealized actuarial losses in AOCI that relate to liabilities that will be settled as a result of pension plan voluntary lump-sum payments, pre-tax	53,000,000
Ongoing annual reduction of pension expense as a result of pension plan voluntary lump-sum payments, pre-tax	4,000,000
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Minimum years of service for employees hired before January 1, 2009 required for participation in a defined benefit pension plan (in years)	5 years
Non-cash charge resulting from expensing unrealized actuarial losses in AOCI that relate to liabilities that will be settled as a result of pension plan voluntary lump-sum payments, pre-tax	68,000,000	0
Accumulated other comprehensive income, unrecognized transition obligation	(1,000,000)
Accumulated other comprehensive income, unrecognized prior service credit	10,000,000
Accumulated other comprehensive income, unrecognized actuarial losses	975,000,000
Prior service cost, expected to be recognized in net periodic benefit credit in next fiscal year	3,000,000
Actuarial loss, expected to be recognized in net periodic benefit cost in next fiscal year	70,000,000
Projected benefit obligation for plans with projected benefit obligation in excess of plan assets	2,400,000,000		2,800,000,000	2,100,000,000
Accumulated benefit obligation for plans with projected benefit obligation in excess of plan assets	2,200,000,000		2,500,000,000	1,900,000,000
Fair value of plan assets for plans with projected benefit obligations in excess of plan assets	1,600,000,000		1,900,000,000	1,700,000,000
Projected benefit obligation for plans with accumulated benefit obligation in excess of plan assets	2,400,000,000		2,700,000,000	671,000,000
Accumulated benefit obligation for plans with accumulated benefit obligation in excess of plan assets	2,200,000,000		2,500,000,000	657,000,000
Fair value of plan assets for plans with accumulated benefit obligation in excess of plan assets	1,600,000,000		1,800,000,000	425,000,000
Accumulated benefit obligation	2,700,000,000		2,700,000,000	2,300,000,000
Contributions and expected future benefit payments	37,000,000
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service credit in AOCI related to postretirement plan ammendment, pre-tax	109,000,000
Prior service credit amortization period, in years	8
Ongoing reduction of annual pre-tax postretirement expense attributable to plan ammendment, pre-tax	21,000,000
Accumulated other comprehensive income, unrecognized prior service credit	(123,000,000)
Accumulated other comprehensive income, unrecognized actuarial losses	67,000,000
Prior service cost, expected to be recognized in net periodic benefit credit in next fiscal year	(18,000,000)
Actuarial loss, expected to be recognized in net periodic benefit cost in next fiscal year	6,000,000
Annual rate of increase in per capita cost of covered health care benefits assumed for transition period (as a percent)	7.25%
Annual rate for per capita cost of covered health care benefits assumed for 2022 and thereafter (as a percent)	5.00%
Year ultimate rate assumed for per capita cost of health care benefits is to be reached	2022
Contributions and expected future benefit payments	$ 13,000,000
Maximum [Member] | Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Annual index on credits used to fund Health Care Reimbursement accounts	3.00%