Balance Sheet Accounts and Supplemental Disclosures - Estimated Amounts to be Amortized from Other Comprehensive Loss (Details) $ in Millions	12 Months Ended
Dec. 31, 2016 USD ($)
Pension Benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Actuarial losses (gains), net	$ 67.8
Prior service costs (credits), net	0.1
Total	67.9
Medical and Life Insurance Benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Actuarial losses (gains), net	(4.1)
Prior service costs (credits), net	(0.2)
Total	$ (4.3)

Amount included in accumulated other comprehensive income (AOCI) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position, including gain (loss), prior service cost (credit), and transition asset (obligation).

No definition available.

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