Weighted-average remaining life of unvested restricted stock units.

No definition available.

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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Aggregate dividends paid during the period for each share of common stock outstanding.

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Total of the carrying values as of the balance sheet date of obligations incurred through that date and payable for obligations related to services received from employees, such as accrued salaries and bonuses, payroll taxes and fringe benefits. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Represents the compensation cost capitalized during the period arising from equity-based compensation arrangements (for example, shares of stock, units, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Unrecognized cost of unvested share-based compensation awards.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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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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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Gross number of share options (or share units) granted during the period.

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No definition available.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of share options (or share units) exercised during the current period.

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The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

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No definition available.

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Total cost of shares repurchased divided by the total number of shares repurchased.

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Number of shares that have been repurchased during the period and are being held in treasury.

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Number of shares of restricted stock determined by relating the portion of time within a reporting period that restricted shares have been outstanding to the total time in that period. Restricted shares are subject to sales, contractual, regulatory or other restrictions that prevent or inhibit the holder from freely disposing of them before the restriction ends.

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CAPITAL STOCK - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended			67 Months Ended
	Jan. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options and restricted stock, anti-dilutive (in shares)		5,600,000	7,300,000	4,700,000
Common stock share purchase, shares (in shares)		40,000,000			40,000,000	40,000,000
Treasury shares acquired (in shares)		7,827,333	0	0	40,000,000
Common stock share repurchase price (in USD per share)		$ 38.99			$ 79.18
Common stock dividends (in USD per share)		$ 1.00	$ 1.00	$ 1.00
Shares authorized and available for grant (in shares)		16,200,000			16,200,000
Intrinsic value of options exercised		$ 0.1	$ 0.2
Shares exercised in the period (in shares)		(29,000)		0
Compensation expense		$ 157.0	142.0	$ 131.0
Stock-settled and cash-settled compensation capitalized		37.0	41.0	$ 40.0
Outstanding liability for the unvested awards		177.0	$ 115.0		$ 177.0
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost related to non-vested awards not yet recognized		6.0			6.0
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost related to non-vested awards not yet recognized		$ 47.0			47.0
Awards granted during period (in shares)		608,236	1,947,506	4,049,023
Weighted average grant date fair value per share (in USD per share)		$ 45.59	$ 62.74	$ 47.37
Compensation expense		$ 101.0	$ 108.0	$ 113.0
Stock-settled and cash-settled compensation capitalized		$ 29.0	35.0	35.0
Unvested restricted stock units (in shares)		3,152,801
Weighted-average remaining life of unvested restricted stock units		8 months
Total fair value of restricted stock awards vested		$ 111.0	$ 135.0	$ 151.0
Outstanding liability for the unvested awards		$ 25.0			$ 25.0
Phantom Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted during period (in shares)		1,973,360
Subsequent Event \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period in which stock options become exercisable	3 years
Total compensation cost related to non-vested awards not yet recognized	$ 25.0
Awards granted during period (in shares)	920,043
Weighted average grant date fair value per share (in USD per share)	$ 27.21
Subsequent Event \| Phantom Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost related to non-vested awards not yet recognized	$ 92.0
Options issued during the period (in shares)	3,393,772
Prior to 2016 \| Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period in which stock options become exercisable		4 years
Period in which stock options expires after grant date		10 years
In or after 2016 \| Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period in which stock options become exercisable		3 years
Period in which stock options expires after grant date		10 years
ALTM \| Subsequent Event \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value per share (in USD per share)	$ 7.51
ALTM \| Subsequent Event \| Phantom Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost related to non-vested awards not yet recognized	$ 10.0
Options issued during the period (in shares)	1,394,526