Employee Benefit Plans, Share Based Compensation, Equity Instruments Other Than Options (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012
Employee stock purchase plan 2008
Employee Stock Purchase Plan
Employee stock purchase plans offering period duration			6 months
Stock issued during period, shares, employee stock purchase plans	1.5	1.9	3.3		3.6
Average price of common stock, per share	$ 18.42	$ 14.90	$ 16.53		$ 16.26
Restricted stock units (RSUs)
Restricted Stock Units, Restricted Stock Awards, and Performance Share Awards Activities [Roll Forward]
Awards granted, number of shares			9.7
Awards vested, number of shares			(4.6)
Awards canceled, number of shares			(2.5)
Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Awards granted, weighted average grant-date fair value (in dollars per share)			$ 20.29
Awards vested, weighted average grant-date fair value (in dollars per share)			$ 27.74
Awards canceled, weighted average grant-date fair value (in dollars per share)			$ 23.14
Performance shares (PSAs)
Restricted Stock Units, Restricted Stock Awards, and Performance Share Awards Activities [Roll Forward]
Awards granted, number of shares			2.2	[1]
Awards vested, number of shares			(1.1)
Awards canceled, number of shares			(2.8)
Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Awards granted, weighted average grant-date fair value (in dollars per share)			$ 21.27	[1]
Awards vested, weighted average grant-date fair value (in dollars per share)			$ 28.27
Awards canceled, weighted average grant-date fair value (in dollars per share)			$ 29.94
Aggregate number of shares subject to PSAs granted			1.1
Minimum shares to be issued on achievement of performance goals in respect of PSAs			0
Maximum shares to be issued on achievement of performance goals in respect of PSAs			2.2
Restricted stock awards (RSAs)
Restricted Stock Units, Restricted Stock Awards, and Performance Share Awards Activities [Roll Forward]
Awards vested, number of shares			(1.1)
Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Awards vested, weighted average grant-date fair value (in dollars per share)			$ 19.59
RSUs, RSAs, and PSAs
Restricted Stock Units, Restricted Stock Awards, and Performance Share Awards Activities [Roll Forward]
Beginning balance, number of shares			26.8
Ending balance, number of shares	26.6		26.6
Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Beginning balance, weighted average grant-date fair value (in dollars per share)			$ 27.76
Ending balance, weighted average grant-date fair value (in dollars per share)	$ 25.05		$ 25.05
Weighted average remaining contractual terms			1 year 3 months 18 days
RSUs and PSAs, aggregate intrinsic value at period end	$ 529.0		$ 529.0
Vested and expected-to-vest RSUs and PSAs, number of shares at period end	22.8		22.8
Vested and expected-to-vest RSUs and PSAs, weighted average grant-date fair value at period end (in dollars per share)	$ 23.57		$ 23.57
Vested and expected-to-vest RSUs and PSAs, weighted average remaining contractual term at period end			1 year 1 month 6 days
Vested and expected-to-vest RSUs and PSAs, aggregate intrinsic value at period end	$ 453.7		$ 453.7

[1] The number of shares subject to PSAs granted represents the aggregate maximum number of shares that may be issued pursuant to the award over its full term. The aggregate number of shares subject to these PSAs that would be issued if performance goals determined by the Compensation Committee are achieved at target is 1.1 million shares. Depending on achievement of such performance goals, the range of shares that could be issued under these awards is 0 to 2.2 million shares.