Employee Benefit Plans (Details) (USD $)	1 Months Ended		3 Months Ended
	May 31, 2011	May 31, 2010	Mar. 31, 2012		Dec. 31, 2011
Share-Based Compensation Plans
Maximum Additional Shares Expire Unexercised, Under 1996 and 2000 Plan			75,000,000
Outstanding Stock Options and RSU's Covering Shares of Common Stock			1,600,000
Stock Option Activities
Beginning Balance, Number of Shares			38,600,000
Beginning Balance, Weighted Average Exercise Price			23.98
Options Granted, Number of Shares			3,000,000
Options Granted, Weighted Average Exercise Price			22.93
Options Canceled, Number of Shares			(500,000)
Options Canceled, Weighted Average Exercise Price			28.48
Options Exercised, Number of Shares			(700,000)
Options Exercised, Weighted Average Exercise Price			12.67
Options Expired, Number of Shares			(200,000)
Options Expired, Weighted Average Exercise Price			26.18
Ending Balance, Number of Shares			40,200,000
Ending Balance, Weighted Average Exercise Price			24.02
Weighted Average Remaining Contractual Term at Period End			3.7
Aggregate Intrinsic Value at Period End			106,400,000
Vested or Expected-to-Vest Options, Number of Shares at Period End			38,300,000
Vested or Expected-to-Vest Options, Weighted Average Exercise Price at Period End			23.80
Vested and Expected-to-Vest Options, Weighted Average Remaining Contractual Term at Period End			3.6
Vested or Expected-to-Vest Options, Aggregate Intrinsic Value at Period End			104,500,000
Exercisable Options, Number of Shares at Period End			27,700,000
Exercisable Options, Weighted Average Exercise Price at Period End			22.47
Exercisable Options, Weighted Average Remaining Contractual Term at Period End			2.9
Exercisable Options, Aggregate Intrinsic Value at Period End			87,700,000
Closing Stock Price At Plan Period End			22.88
Intrinsic Value of Options Exercise, Pre-Tax			6,900,000
Total Fair Value of Options Vested			27,900,000
Employee Stock Purchase Plan 2008 [Member]
Share-Based Compensation Plans
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price			15.00%
Periodic Payroll Deduction - Percentage of Base Salary			10.00%
Maximum Purchase of Common Stock, Shares			6,000
Maximum Purchase of Common Stock, Value			25,000
Stock Options [Member]
Stock Option Activities
Share-based compensation stock option contractual life from grant date since 2006, in years			7
Employee Stock Purchase Plan [Member]
Share-Based Compensation Plans
ESPP purchase period, share limitation (in months)			12
ESPP purchase period, value limitation (in calendar years)			1
Stock Option Activities
Share-based compensation stock option contractual life from grant date, prior to 2006, in years			10
Equity Incentive Plan 2006 [Member]
Share-Based Compensation Plans
Number of Shares in Authorized			64,500,000
Additional Authorized Share Reserve Approved By Shareholders	30,000,000	30,000,000
Number of Shares Outstanding			64,900,000
Number of Shares Available for Future Issuance			22,200,000		41,100,000
Stock Option Activities
Options Granted, Number of Shares			3,000,000
Options Canceled, Number of Shares			(500,000)	[1]
Options Expired, Number of Shares			(200,000)	[1]

[1] Includes canceled or expired options under the 1996 Plan and the 2000 Plan that expired unexercised after May 18, 2006, which become available for grant under the 2006 Plan according to its terms.