Stock-Based Compensation (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2011 Y	Dec. 31, 2010	Dec. 31, 2009
Stock-Based Compensation (Textual) [Abstract]
Number of options, exercised	121,089
Weighted-average period	4
Total fair value of shares vested		$ 7,000,000	$ 2,000,000
Vesting period	3 years
Additional Stock Based Compensation (Textual) [Abstract]
Total compensation expense for stock-based compensation plans	45,000,000	55,000,000	54,000,000
Total income tax benefit recognized for stock-based compensation plans	17,000,000	21,000,000	20,000,000
Common Shares available for future grant under our compensation plans	29,250,626
Limit to granting options under any long-term compensation plan	Aggregate amount that exceeds 6% of our outstanding common shares in any rolling three-year period
Exercise rate of stock options granted to employees	25.00%	33.33%
Maximum Expiration period of Options from their grant date	10 years
Weighted-average grant-date fair value of options	$ 4.11	$ 3.71	$ 2.37
Total intrinsic value of exercised options	300,000	200,000	0
Cash received from options exercised	700,000	400,000
Actual tax benefit realized for the tax deductions from options exercised	100,000	100,000
Employer matching contribution in mandatory deferred incentive awards	15.00%
Mandatory deferred incentive awards vest at the rate	33.33%
Voluntary deferral programs provide an employer match, minimum	6.00%
Voluntary deferral programs provide an employer match, maximum	15.00%
Paid stock-based liabilities	0	0	0
Stock Options [Member]
Stock-Based Compensation (Textual) [Abstract]
Number of options, exercised	121,089	79,786	0
Unrecognized compensation cost related to nonvested options expected to vest	9,000,000
Weighted-average period	2.6
Long-Term Incentive Compensation Program [Member]
Stock-Based Compensation (Textual) [Abstract]
Unrecognized compensation cost related to nonvested options expected to vest	28,000,000
Weighted-average period	2.8
Paid cash awards in connection with vested performance shares	0	0	0
Weighted-average grant date fair value granted	$ 9.12	$ 6.74	$ 6.56
Total fair value of shares vested	10,000,000
Vesting period	Three-year or four-year
Long-Term Incentive Compensation Program [Member] | Vesting Contingent on Service Conditions [Member]
Stock-Based Compensation (Textual) [Abstract]
Weighted-average grant date fair value granted	$ 9.23
Number of time-lapsed restricted stock awards granted to recognize outstanding performance	4,323,971	1,594,104
Long-Term Incentive Compensation Program [Member] | Vesting Contingent on Performance and Service Conditions [Member]
Stock-Based Compensation (Textual) [Abstract]
Weighted-average grant date fair value granted	$ 8.79
Number of time-lapsed restricted stock awards granted to recognize outstanding performance	1,061,987	1,892,176
Other Restricted Stock Awards [Member]
Stock-Based Compensation (Textual) [Abstract]
Unrecognized compensation cost related to nonvested options expected to vest	9,000,000
Weighted-average period	1.7
Weighted-average grant date fair value granted	$ 9.25	$ 6.96	$ 6.44
Total fair value of shares vested	29,000,000	23,000,000	3,000,000
Number of time-lapsed restricted stock awards granted to recognize outstanding performance	3,686,784	5,461,855
Deferred Compensation Plans [Member]
Stock-Based Compensation (Textual) [Abstract]
Unrecognized compensation cost related to nonvested options expected to vest	4,000,000
Weighted-average period	1.8
Weighted-average grant date fair value granted	$ 8.03	$ 7.93	$ 6.83
Total fair value of shares vested	5,000,000	6,000,000	6,000,000
Vesting period	After three years
Number of time-lapsed restricted stock awards granted to recognize outstanding performance	1,338,325	890,939
Discounted Stock Purchase Plan [Member]
Stock-Based Compensation (Textual) [Abstract]
Employee discount on the purchase of stock through Discounted Stock Purchase Plan	10.00%
Purchases are limited to any month	10,000
Purchases are limited to any calendar year	$ 50,000
Issuance of shares	297,091	241,445	371,417
Weighted average cost of Shares issued under the plan	7.71	7.69	6.31