Stock Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2015

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 2015, 2014 and 2013 are as follows:

	2015	2014	2013
Risk-free interest rate	1.78%	1.88%	1.03%-1.30%
Expected life (in years)	6.0	6.0	6.0
Expected volatility	23.75%	24.2%	23.6%-24.1%
Expected dividend yield	1.97%	2.08%	2.48%-2.54%

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, 2015 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, 2015	17,995,082		$	30.97
Granted	1,574,706		$	56.84
Exercised	(4,607,079	)	$	29.24
Forfeited	(131,126	)	$	46.43
Expired	(54,779	)	$	30.45
Balance at December 31, 2015	14,776,804		$	34.14	5.4 years	$	328,225
Options vested or expected to vest at December 31, 2015	14,584,291		$	34.04	5.4 years	$	325,388
Options exercisable at December 31, 2015	10,104,569		$	28.88	4.3 years	$	276,975

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, 2015 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, 2015	2,097,730		$	38.74	868,008		$	37.56
Granted	1,737,354		$	56.81	210,829		$	56.84
Vested	(1,264,076	)	$	35.56	(373,449	)	$	31.99
Forfeited	(111,715	)	$	52.67	(27,223	)	$	46.91
Non-vested balance at December 31, 2015	2,459,293		$	52.51	678,165		$	46.25

Summary of restricted stock awards activity

A summary of the status of the Company's restricted stock awards as of December 31, 2015 and changes during the period then ended is presented below:

	Shares		Weighted Average Grant Date Fair Value
Non-vested balance at January 1, 2015	7,200		$	46.14
Granted	—		$	—
Vested	(7,200	)	$	46.14
Forfeited	—		$	—
Non-vested balance at December 31, 2015	—		$	—