Debt (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Debt Disclosure [Abstract]
Long-term Debt, Fair Value	$ 295		$ 295		$ 315
Interest Expense, Debt	$ 2	$ 2	$ 5	$ 4