Income Taxes - Additional Information (Details) (USD $)	3 Months Ended				6 Months Ended				3 Months Ended
	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2013	Mar. 31, 2013 Subsidiary	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 Group Eight [Member]	Jul. 31, 2013 Senior Notes Sold In 2013 [Member]	Jun. 30, 2014 ITALY	Mar. 31, 2013 UNITED KINGDOM Valuation Allowance [Member]
Income Taxes [Line Items]
Income Tax Expense (Benefit)	$ 33,000,000		$ 35,000,000		$ 67,000,000	$ 62,000,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate	35.00%		35.00%		35.00%	35.00%
Income Tax Reconciliation, Repatriation of Foreign Earnings	2,000,000		2,000,000		3,000,000	4,000,000
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	1,000,000	4,000,000
Income Tax Expense For Uncertain Tax Positions									2,000,000
Number of subsidiaries in which Noncontrolling Interests were purchased				3
Income Tax Expense Reduction										2,000,000
Senior notes issued								750,000,000
Deferred Tax Assets, Valuation Allowance							$ 675,000,000