STOCK-BASED COMPENSATION.

6 Months Ended

Jun. 30, 2019

Share-based Payment Arrangement [Abstract]

STOCK-BASED COMPENSATION.

STOCK OPTIONS.

The following table summarizes the status of, and changes in, our stock options during the six months ended June 30, 2019.



	Options		Weighted- average exercise price
Outstanding at December 31, 2018	11,300,393		$	69.05
Exercised	(1,765,404	)	$	62.39
Forfeited	(86,456	)	$	76.68
Expired	(7,809	)	$	59.07
Outstanding at June 30, 2019	9,440,724		$	70.23
Exercisable at June 30, 2019	7,485,674		$	68.59

RESTRICTED SHARES AND STOCK UNITS.

The following table summarizes the status of, and changes in, our nonvested restricted shares and restricted stock units during the six months ended June 30, 2019.



	Restricted shares		Restricted stock units		Weighted-average fair value
Nonvested at December 31, 2018	136,964		6,603,920		$	87.07
Time-based grants	7,404		34,221		$	100.03
Vested	(8,710	)	(55,360	)	$	97.65
Forfeited	(7,119	)	(269,073	)	$	87.81
Nonvested at June 30, 2019	128,539		6,313,708		$	87.02

Nonvested at June 30, 2019, includes 2,400 performance-based restricted shares and 450,727 performance-based restricted stock units. These nonvested performance-based restricted shares and units include 2,400 restricted shares and 289,906 restricted stock units for which the performance period has lapsed, and the performance threshold has been met.

FUTURE STOCK-BASED COMPENSATION EXPENSE.

The following table presents the compensation expense to be recognized over the remaining vesting periods of the stock-based awards outstanding at June 30, 2019. Estimated future compensation expense will change to reflect future grants of restricted stock awards and units, future option grants, changes in the probability of performance thresholds being met, and adjustments for actual forfeitures.



(in millions)
Third quarter 2019	$	48.9
Fourth quarter 2019	43.9
2020	100.7
2021 through 2024	80.3
Total	$	273.8