Stock Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2016

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Option pricing valuation model for options granted

The assumptions used in the Black-Scholes option pricing valuation model for options granted by the Company in 2016, 2015 and 2014 are as follows:

	2016	2015	2014
Risk-free interest rate	1.39%	1.78%	1.88%
Expected life (in years)	6.0	6.0	6.0
Expected volatility	25.55%	23.75%	24.2%
Expected dividend yield	2.15%	1.97%	2.08%

Summary of the status of MMC's stock option awards

A summary of the status of the Company’s stock option awards as of December 31, 2016 and changes during the year then ended is presented below:

	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value ($000)
Balance at January 1, 2016	14,776,804		$	34.14
Granted	2,167,645		$	57.55
Exercised	(3,593,033	)	$	29.32
Forfeited	(91,016	)	$	53.58
Expired	(17,871	)	$	30.13
Balance at December 31, 2016	13,242,529		$	39.15	5.7 years	$	377,580
Options vested or expected to vest at December 31, 2016	13,055,049		$	38.95	5.7 years	$	374,871
Options exercisable at December 31, 2016	8,598,826		$	31.63	4.4 years	$	309,778

Summary of restricted stock units and performance stock units

A summary of the status of the Company's restricted stock units and performance stock units as of December 31, 2016 and changes during the period then ended is presented below:

	Restricted Stock Units				Performance Stock Units
	Shares		Weighted Average Grant Date Fair Value		Shares		Weighted Average Grant Date Fair Value
Non-vested balance at January 1, 2016	2,459,293		$	52.51	678,165		$	46.25
Granted	1,844,661		$	57.54	323,990		$	57.47
Vested	(1,100,706	)	$	49.62	(260,089	)	$	36.56
Forfeited	(159,219	)	$	56.41	(20,049	)	$	54.49
Non-vested balance at December 31, 2016	3,044,029		$	56.40	722,017		$	54.68