Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Fair Value of Financial Instruments
Long-term Investments	$ 160		$ 160
Total long-term debt	11,700		11,700
Estimated fair value of long-term debt	12,300		12,300
Related Party Transaction, Amounts of Transaction	$ 3	$ 11	$ 7	$ 27