Common Stock (Details) (Class A Common Stock [Member], USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Equity, Class of Treasury Stock [Line Items]
Stock issued during period from exercise of warrants (in shares)	579,776	2,600,000	2,600,000	2,600,000
Income Tax Withholding [Member]
Equity, Class of Treasury Stock [Line Items]
Shares withheld in payment of income tax withholding owed by employees (in shares)	7,206	7,245	122,642	113,345
Total consideration of stock purchase	$ 1	$ 1	$ 18	$ 11