Employee Benefit Plans (Narrative) (Details) (USD $) Share data in Millions, unless otherwise specified	6 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
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)			13
Market value of employer's Common stock held under 401 (k) plan			$ 549,000,000
Cash dividend received on employer's Common stock held under 401 (k) plan			10,000,000
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			174,000,000
Improvement in pension underfunding as a result of pension plan voluntary lump-sum payments	40,000,000			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
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets, Aggregate Projected Benefit obligation	2,400,000,000		2,200,000,000	2,400,000,000
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	68,000,000	0	0	68,000,000
Accumulated other comprehensive income, unrecognized transition obligation			1,000,000
Accumulated other comprehensive income, unrecognized prior service cost (credit)			6,000,000
Accumulated other comprehensive income, unrecognized actuarial losses			589,000,000
Prior service cost (credit), expected to be recognized in net periodic benefit cost (credit) in next fiscal year			3,000,000
Actuarial loss, expected to be recognized in net periodic benefit cost in next fiscal year			35,000,000
Fair value of plan assets for plans with projected benefit obligations in excess of plan assets	1,600,000,000		1,600,000,000	1,600,000,000
Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets, Aggregate Benefit Obligation	2,200,000,000		2,000,000,000	2,200,000,000
Projected benefit obligation for plans with accumulated benefit obligation in excess of plan assets	2,400,000,000		2,100,000,000	2,400,000,000
Accumulated benefit obligation for plans with accumulated benefit obligation in excess of plan assets	2,200,000,000		1,900,000,000	2,200,000,000
Fair value of plan assets for plans with accumulated benefit obligation in excess of plan assets	1,600,000,000		1,600,000,000	1,600,000,000
Accumulated benefit obligation	2,700,000,000		2,600,000,000	2,700,000,000
Contributions and expected future benefit payments			41,000,000
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service credit in AOCI related to postretirement plan amendment, pre-tax	109,000,000			109,000,000
Prior service credit amortization period, in years			8 years
Accumulated other comprehensive income, unrecognized prior service cost (credit)			(106,000,000)
Accumulated other comprehensive income, unrecognized actuarial losses			28,000,000
Prior service cost (credit), expected to be recognized in net periodic benefit cost (credit) in next fiscal year			(18,000,000)
Actuarial loss, expected to be recognized in net periodic benefit cost in next fiscal year			1,000,000
Annual rate of increase in per capita cost of covered health care benefits assumed for transition period (as a percent)			7.00%
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			$ 11,000,000
Maximum [Member] | Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Annual index on credits used to fund Health Care Reimbursement accounts	3.00%		3.00%	3.00%