Fair Value Measurements (Details Textual) (USD $) In Billions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
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
Cash and cash equivalents	$ 20.6	$ 20.9
Maturity period of bank time deposits, minimum, classified as time deposits (in days)	90 days
Time deposits	1.4	0.7
Restricted cash	1.0	1.5
Carrying Value of Long-term Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net carrying value	12.0	6.1
Fair Value of Long-term Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net carrying value	12.3	6.8
Level 1 [Member] | Corporate Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt	11.6
Level 2 [Member] | Other Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt	$ 0.7