Commitments and Contingencies (Pace, Piedmont, Pasadena - Narrative) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2012	Sep. 30, 2008	Sep. 30, 2006
Pace, Florida [Member]
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	$ 29,800,000			$ 42,000,000
Years to complete environmental remediation				20 years beginning in 2006
Change in estimated exposure	0
Pace, Florida [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Estimate of possible exposure from environmental loss contingencies				$ 42,000,000
Pace, Florida [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Estimate of possible exposure from environmental loss contingencies				52,000,000
Pace, Florida [Member] | Segment Discontinued Operations [Member]
Loss Contingencies [Line Items]
Pretax environmental expense				$ 42,000,000
Piedmont, South Carolina [Member]
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	$ 17,300,000		$ 24,000,000
Years to complete environmental remediation	until 2019 to complete source area remediation with groundwater recovery and treatment, continuing through 2029
Change in estimated exposure	$ 0
Piedmont, South Carolina [Member] | Segment Discontinued Operations [Member]
Loss Contingencies [Line Items]
Pretax environmental expense			$ 24,000,000
Pasadena, Texas Member [Member]
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	$ 10,300,000
Years to complete environmental remediation	until 2042
Total anticipated exposure		$ 13,000,000
Change in estimated exposure	$ 0