Certain Employee Benefit and Stock Based Compensation Plans (Nonvested Incentive/Performance Unit Share Awards and Restricted Stock/Unit Awards - Rollforward) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Nonvested Incentive Performance Unit Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested Incentive/Performance Unit Share Awards and Restricted Stock/Share Unit Awards, Beginning balance	1,119
Granted	885
Vested/Released	(326)
Forfeited	(20)
Nonvested Incentive/Performance Unit Share Awards and Restricted Stock/hare Unit Awards, Ending balance	1,658
Weighted-average grant date fair value, beginning of period	$ 61.14
Weighted-average grant date fair value, granted shares	$ 63.86
Weighted-average grant date fair value, vested/release shares	$ 58.26
Weighted-average grant date fair value, forfeited shares	$ 59.36
Weighted-average grant date fair value, end of period	$ 63.18
Nonvested Restricted Stock Share Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested Incentive/Performance Unit Share Awards and Restricted Stock/Share Unit Awards, Beginning balance	3,061
Granted	1,123
Vested/Released	(611)
Forfeited	(125)
Nonvested Incentive/Performance Unit Share Awards and Restricted Stock/hare Unit Awards, Ending balance	3,448
Weighted-average grant date fair value, beginning of period	$ 60.04
Weighted-average grant date fair value, granted shares	$ 63.49
Weighted-average grant date fair value, vested/release shares	$ 55.07
Weighted-average grant date fair value, forfeited shares	$ 61.76
Weighted-average grant date fair value, end of period	$ 61.98