Summary of Accounting Policies - Redeemable Noncontrolling Interests (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended	1 Months Ended
	Dec. 31, 2014 joint_venture	May 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Basis of Presentation and Summary of Significant Accounting Policies [Line Items]
Finite Lived Intangible Assets Amortization Expenses	$ 4		$ 5	$ 5
Number of joint ventures	5
CHINA
Basis of Presentation and Summary of Significant Accounting Policies [Line Items]
Buisness Sale Percentage of Voting Interest Sold		45.00%
Proceeds from Sale of Equity Method Investments		$ 4
Equity Ownership Percentage after Additional Sale		55.00%
Equity Ownership Percentage Before Additional Sale		100.00%