Common Stock and Stock Plans, Summary of Performance Awards (Details) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested, shares, end of period	10,294,881
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested, shares, beginning of period	6,404,965
Nonvested, fair value, beginning of period	$ 29.68
Granted, shares	3,889,916
Granted, weighted-average grant-date fair value	$ 31.44	$ 31.26	$ 27.46
Vested, shares	0
Nonvested, shares, end of period		6,404,965
Nonvested, fair value, end of period	$ 30.35	$ 29.68

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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- Definition

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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