Capital Stock (Narrative) (Details) (USD $)	1 Months Ended					12 Months Ended
	Dec. 31, 2012	Nov. 30, 2012	Jul. 31, 2012	Apr. 30, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Capital Stock [Abstract]
Value of shares repurchased during period	$ 50,000,000		$ 200,000,000		$ 100,000,000	$ 257,000,000	$ 312,000,000	$ 255,000,000
Additonal shares received based on volume-weighted average stock price during term of transaction		400,517		4,653
Restricted Stock, Shares Repurchased for Tax Withholdings						192,196
Stock Purchase Program, Authorized Replacement Amount	800,000,000
Preferred stock, shares authorized	30,000,000				30,000,000	30,000,000	30,000,000
Debt restrictions on Company's ability to pay dividends and repurchase its common stock						The amount of restricted payments permitted to be made, including dividends and repurchases of the Company’s common stock, is generally limited to the cumulative excess of $200 plus 50% of adjusted net income plus proceeds from the exercise of employee stock options over the aggregate of restricted payments made since July 2004.
Limited cumulative excess amount, maximum	$ 200					$ 200
Debt restrictions on payment of dividends and repurchase of common stock, percentage adjustment						50.00%