Fair Value Measurements (Details Textual) - USD ($) $ in Billions	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 8.8	$ 11.0
Restricted cash	0.9	1.1
Level 1 [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt	31.7
Level 2 [Member] | Other Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt	0.9
Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net carrying value	31.5	25.6
Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net carrying value	$ 32.6	$ 25.9
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Maturity period of primarily bank time deposits, maximum, classified as cash equivalents and money market funds (in days)	90 days