Debt and Credit Arrangements (Tables)

12 Months Ended

Dec. 31, 2011

Debt and Credit Arrangements [Abstract]

Long term debt

	December 31
	2011		2010
	(in millions)
6% notes due November 15, 2011	$	—	$	400
5.2% notes due April 1, 2013		275		275
5.75% notes due May 15, 2018		600		600
6.6% debentures due August 15, 2018		100		100
6.8% debentures due November 15, 2031		200		200
6% notes due May 11, 2037		800		800
6.5% notes due May 15, 2038		600		600
6.375% capital securities due March 29, 2067		1,000		1,000
	$	3,575	$	3,975

Amounts of long term debt due annually

Years Ending December 31	(in millions)
2012	$	—
2013		275
2014		—
2015		—
2016		—