Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

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Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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- Definition

Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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Stockholders' Equity and Earnings Per Common Share Shares Repurchased (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Treasury Stock
Share Repurchase Table [Line Items]
Treasury Stock Acquired in Open Market Value			$ 500.6	$ 419.9	$ 356.0
Treasury Stock, Shares, Acquired			23.6	17.7	16.4
Retirement of Common Shares (2)
Share Repurchase Table [Line Items]
Stock Repurchased and Retired During Period, Shares	0.6	7.1	0	7.7	0
Stock Repurchased and Retired During Period, Value			0	200.0	0
Total
Share Repurchase Table [Line Items]
Stock Repurchased During Period, Shares			23.6	25.4	16.4
Stock Repurchased During Period, Value			$ 500.6	$ 619.9	$ 356.0