For defined benefit pension plans, the actuarial present value of benefits (whether vested or nonvested) attributed by the pension benefit formula to employee service rendered before a specified date and based on employee service and compensation (if applicable) before that date. The accumulated benefit obligation differs from the projected benefit obligation in that it includes no assumption about future compensation levels. For plans with flat-benefit or nonpay-related pension benefit formulas, the accumulated benefit obligation and the projected benefit obligation are the same.

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-Name Accounting Standards Codification

-Glossary Accumulated Benefit Obligation

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The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Actual Return on Plan Assets (Component of Net Periodic Postretirement Benefit Cost)

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-Glossary Actual Return on Plan Assets (Component of Net Periodic Pension Cost)

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Amount of gain (loss) related to change in benefit obligation resulting from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover, salary, and temporary deviation from the substantive plan.

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1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date.

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-Glossary Projected Benefit Obligation

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-Glossary Accumulated Postretirement Benefit Obligation

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The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets.

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-Glossary Postretirement Benefits

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The increase in the fair value of plan assets from contributions made by the employer.

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The amount of contributions made by plan participants. This item represents a periodic increase to the plan obligation and an increase to plan assets.

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Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

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The funded status is measured as the difference between the fair value of plan assets and the benefit obligation. Will normally be the same as the net Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total.

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The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

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Changes in the defined benefit obligation, not otherwise separately disclosed in the financial statements.

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The amount of increase or decrease due to a change in the terms of an existing plan or the initiation of a new plan. A plan amendment may increase or decrease benefits, including those attributed to years of service already rendered.

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The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

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Obligations and Funded Status (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended	12 Months Ended
	Dec. 31, 2012	Jun. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in the Projected Benefit Obligation (PBO):
Plan amendments	$ 29.8	$ 34.7			$ 5.3
Actuarial (gain) loss			5.2	42.2	80.0
Change in Plan Assets:
Fair value of plan assets at beginning of year		536.8	536.8
Fair value of plan assets at end of year	536.8		583.8	536.8
Pension Benefits
Change in the Projected Benefit Obligation (PBO):
Projected benefit obligation at beginning of year		722.5	722.5	639.5
Service cost			11.4	12.1
Interest cost			30.1	30.7
Plan amendments				0.4
Actuarial (gain) loss			(73.0)	66.0
Benefits paid			(28.7)	(26.2)
Projected benefit obligation at end of year	722.5		662.3	722.5
Accumulated benefit obligation at end of year (excludes the impact of future compensation increases)	703.3		648.5	703.3
Change in Plan Assets:
Fair value of plan assets at beginning of year		536.8	536.8	477.9
Actual return on plan assets			74.6	63.7
Employer contributions			1.1	21.4
Benefits paid			(28.7)	(26.2)
Fair value of plan assets at end of year	536.8		583.8	536.8
Funded status (Fair value of plan assets less PBO)	(185.7)		(78.5)	(185.7)
Postretirement Benefits
Change in the Projected Benefit Obligation (PBO):
Projected benefit obligation at beginning of year		73.3	73.3	93.9
Service cost			0.3	0.5
Interest cost			1.7	3.9
Plan amendments			(34.7)	(29.8)
Actuarial (gain) loss		4.0	(0.3)	9.9
Participants' contributions			0.5	0.8
Benefits paid			(7.0)	(6.4)
Medicare Part D reimbursement			0.4	0.5
Projected benefit obligation at end of year	73.3		34.2	73.3
Change in Plan Assets:
Employer contributions			6.1	5.1
Participants' contributions			0.5	0.8
Medicare Part D reimbursement			0.4	0.5
Benefits paid			(7.0)	(6.4)
Funded status (Fair value of plan assets less PBO)	$ (73.3)		$ (34.2)	$ (73.3)