For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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This represents the noncurrent liability recognized in the balance sheet that is associated with the defined benefit pension plans.

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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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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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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Amount of employer's best estimate of contributions expected to be paid to the plan during the next fiscal year beginning after the date of the latest statement of financial position.

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Retirement Benefits - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Nov. 30, 2015	Feb. 28, 2015
Defined Benefit Plan Disclosure [Line Items]
Unfunded pension obligation	$ 575.0	$ 580.6	$ 566.2	$ 479.1
Cash contributions expected to make	$ 30.0
Subsidiary Concentration Risk [Member] \| Unfunded Pension Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of unfunded pension benefit obligation for tax-qualified pension plan	82.00%
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit pension plan assets, total		931.4
Projected benefit obligations, total		1,531.0
Unfunded pension obligation		$ 580.6