Debt (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Total debt	$ 799	$ 1,256
Less: short-term debt including current maturities	0	457
Long-term debt	799	799
Annual long term debt maturity year one	0
Annual long term debt maturity year two	0
Annual long term debt maturity year three	0
Annual long term debt maturity year four	400
Annual long term debt maturity after year five	399
Commitment fee minimum percentage	0.20%
Commitment fee maximum percentage	0.45%
5.9% Senior Notes, due 2017 [Member]
Debt Instrument [Line Items]
Senior Notes	400	400
Interest rate	5.90%	5.90%
Unamortized debt discount on senior notes	1
6.55% Senior Notes, due 2037 [Member]
Debt Instrument [Line Items]
Senior Notes	399	399
Interest rate	6.55%	6.55%
Unamortized debt discount on senior notes	1
Three Years Facility [Member]
Debt Instrument [Line Items]
Current commitment fee	0.25%
Commercial Paper [Member]
Debt Instrument [Line Items]
Short-term debt	$ 0	$ 457