Consolidated Statements of Changes in Equity (USD $) In Millions, except Share data	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Loss	Additional Paid-in Capital [Member]
Beginning Balance, shares at Dec. 31, 2009		138,632,000
Net Income	$ 441		$ 441
Dividends declared on common stock	(305)		(305)
Ending Balance at Dec. 31, 2010	4,009	1,386	829	(16)	1,810
Ending Balance, shares at Dec. 31, 2010		138,632,000
Net Income	437		437
Dividends declared on common stock	(306)		(306)
Benefit obligations, net of tax	(4)			(4)
Ending Balance at Dec. 31, 2011	4,136	1,386	960	(20)	1,810
Ending Balance, shares at Dec. 31, 2011	138,632,324	138,632,000
Net Income	486		486
Dividends declared on common stock	(317)		(317)
Benefit obligations, net of tax	2			(2)
Ending Balance at Dec. 31, 2012	$ 4,303	$ 1,386	$ 1,129	$ (22)	$ 1,810
Ending Balance, shares at Dec. 31, 2012	138,632,324	138,632,000