Stock-Based Compensation Plans (Stock Option Activity) (Details) - $ / shares	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Shares
Closing Balance (in shares)	13,593,156
Options outstanding - end of the year (in shares)	6,824,433
Per share weighted average exercise prices
Closing Balance (in dollars per shares)	$ 15.30
Options exercisable - end of the year (in dollars per share)	$ 20.23
Stock Options
Shares
Closing Balance (in shares)	10,495,039	9,122,762
Granted (in shares)	4,932,467	2,553,510
Canceled (in shares)	(258,509)	(63,517)
Expired (in shares)	(1,575,841)	(1,117,716)
Closing Balance (in shares)	13,593,156	10,495,039
Options outstanding - end of the year (in shares)	6,824,433	6,690,250
Per share weighted average exercise prices
Opening Balance (in dollars per shares)	$ 21.67	$ 27.13
Granted (in dollars per share)	8.47	13.16
Canceled (in dollars per share)	13.09	20.34
Expired (in dollars per share)	36.86	46.88
Closing Balance (in dollars per shares)	15.30	21.67
Options exercisable - end of the year (in dollars per share)	$ 20.23	$ 25.57

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Net number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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