Accounting for the Impairment or Disposal of Long-Lived Assets Assets Held for Sale (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Long Lived Assets Held-for-sale [Line Items]
Proceeds from Sale of Property, Plant, and Equipment	$ 491.8	$ 228.5	$ 365.2
Portfolio Sale, Second Settlement [Member]
Long Lived Assets Held-for-sale [Line Items]
Proceeds from Sale of Real Estate	$ 329.6
Industrial Other [Member] | Portfolio Sale, Second Settlement [Member]
Long Lived Assets Held-for-sale [Line Items]
Number of Real Estate Properties	47
Area of Land	19
Square Footage of Real Estate Property	2,600,000
Southeastern PA [Member] | Portfolio Sale, Second Settlement [Member]
Long Lived Assets Held-for-sale [Line Items]
Number of Real Estate Properties	1
Square Footage of Real Estate Property	37,000