Retirement Benefits (Tables)

12 Months Ended

Dec. 31, 2013

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]

Schedule of weighted average actuarial assumptions utilized defined benefit plans

The weighted average actuarial assumptions utilized in determining the above amounts for the U.S. defined benefit and other U.S. postretirement plans as of the end of the year are as follows:

	U.S. Pension Benefits				U.S. Postretirement Benefits
	2013		2012		2013		2012
Weighted average assumptions:
Discount rate (for expense)	4.45	%	5.15	%	4.25	%	5.10	%
Expected return on plan assets	8.75	%	8.75	%	—		—
Rate of compensation increase (for expense)	2.00	%	2.00	%	—		—
Discount rate (for benefit obligation)	5.30	%	4.45	%	5.17	%	4.25	%
Rate of compensation increase (for benefit obligation)	2.00	%	2.00	%	—		—

The weighted average actuarial assumptions utilized for the U.S. and significant non-U.S. defined benefit plans and postretirement benefit plans are as follows:

	Pension  Benefits				Postretirement Benefits
	2013		2012		2013		2012
Weighted average assumptions:
Discount rate (for expense)	4.38	%	4.91	%	4.32	%	5.05	%
Expected return on plan assets	7.68	%	8.03	%	—		—
Rate of compensation increase (for expense)	2.43	%	3.09	%	—		—
Discount rate (for benefit obligation)	4.82	%	4.38	%	5.03	%	4.32	%
Rate of compensation increase (for benefit obligation)	2.64	%	2.43	%	—		—

The weighted average actuarial assumptions utilized for the non-U.S. defined and postretirement benefit plans as of the end of the year are as follows:

	Non-U.S. Pension Benefits				Non-U.S. Postretirement Benefits
	2013		2012		2013		2012
Weighted average assumptions:
Discount rate (for expense)	4.33	%	4.77	%	4.45	%	4.95	%
Expected return on plan assets	7.17	%	7.68	%	—		—
Rate of compensation increase (for expense)	2.69	%	3.73	%	—		—
Discount rate (for benefit obligation)	4.55	%	4.33	%	4.80	%	4.45	%
Rate of compensation increase (for benefit obligation)	2.99	%	2.69	%	—		—

Schedule of components of net periodic benefit cost for U.S. defined benefit and other postretirement benefit plans

The components of the net periodic benefit cost for the non-U.S. defined benefit and other postretirement benefit plans and the curtailment, settlement and termination expenses are as follows:

For the Years Ended December 31,	Non-U.S. Pension Benefits									Non-U.S. Postretirement Benefits
(In millions of dollars)	2013			2012			2011			2013		2012			2011
Service cost	$	148		$	147		$	143		$	2	$	2		$	2
Interest cost	352			366			378			4		5			5
Expected return on plan assets	(587		)	(583		)	(572		)	—		—			—
Amortization of prior service cost	(6		)	(3		)	(3		)	—		(1		)	—
Recognized actuarial loss	108			118			115			2		1			—
Net periodic benefit cost	15			45			61			8		7			7
Settlement loss	—			1			—			—		—			—
Curtailment credit	—			(1		)	—			—		—			—
Special termination benefits	—			—			—			—		—			—
Total cost	$	15		$	45		$	61		$	8	$	7		$	7

The components of the net periodic benefit cost for defined benefit and other postretirement plans are as follows:

Combined U.S. and significant non-U.S. Plans	Pension									Postretirement
For the Years Ended December 31,	Benefits									Benefits
(In millions of dollars)	2013			2012			2011			2013		2012			2011
Service cost	$	252		$	240		$	226		$	5	$	5		$	5
Interest cost	581			596			609			11		13			13
Expected return on plan assets	(911		)	(905		)	(887		)	—		—			—
Amortization of prior service credit	(22		)	(19		)	(19		)	—		(14		)	(13		)
Recognized actuarial loss (credit)	315			270			215			2		—			(4		)
Net periodic benefit cost	$	215		$	182		$	144		$	18	$	4		$	1

The components of the net periodic benefit cost for the U.S. defined benefit and other postretirement benefit plans are as follows:

U.S. Plans only	Pension Benefits									Postretirement Benefits
For the Years Ended December 31,
(In millions of dollars)	2013			2012			2011			2013		2012			2011
Service cost	$	104		$	93		$	83		$	3	$	3		$	3
Interest cost	229			230			231			7		8			8
Expected return on plan assets	(324		)	(322		)	(315		)	—		—			—
Amortization of prior service credit	(16		)	(16		)	(16		)	—		(13		)	(13		)
Recognized actuarial loss (credit)	207			152			100			—		(1		)	(4		)
Net periodic benefit cost (credit)	$	200		$	137		$	83		$	10	$	(3	)	$	(6	)

Schedule of MMC's defined benefit plans and postretirement plans

The following schedules provide information concerning the Company’s non-U.S. defined benefit pension plans and non-U.S. postretirement benefit plans:

	Non-U.S. Pension Benefits						Non-U.S. Postretirement Benefits
(In millions of dollars)	2013			2012			2013			2012
Change in benefit obligation:
Benefit obligation at beginning of year	$	8,579		$	7,717		$	107		$	91
Service cost	148			147			2			2
Interest cost	352			366			4			5
Employee contributions	11			11			—			—
Actuarial (gain) loss	(53		)	419			(8		)	10
Plan amendments	—			(71		)	—			—
Effect of settlement	(2		)	(11		)	—			—
Effect of curtailment	—			(3		)	—			(1		)
Benefits paid	(293		)	(278		)	(4		)	(4		)
Foreign currency changes	(31		)	280			(4		)	4
Other	—			2			—			—
Benefit obligation December 31	$	8,711		$	8,579		$	97		$	107
Change in plan assets:
Fair value of plan assets at beginning of year	$	8,312		$	7,206		$	—		$	—
Actual return on plan assets	698			721			—			—
Effect of settlement	(2		)	(11		)	—			—
Company contributions	620			389			4			4
Employee contributions	11			11			—			—
Benefits paid	(293		)	(278		)	(4		)	(4		)
Foreign currency changes	5			273			—			—
Other	—			1			—			—
Fair value of plan assets, December 31	$	9,351		$	8,312		$	—		$	—
Net funded status, December 31	$	640		$	(267	)	$	(97	)	$	(107	)
Amounts recognized in the consolidated balance sheets:
Non-current assets	$	977		$	258		$	—		$	—
Current liabilities	(5		)	(6		)	(4		)	(4		)
Non-current liabilities	(332		)	(519		)	(93		)	(103		)
Net asset (liability) recognized, December 31	$	640		$	(267	)	$	(97	)	$	(107	)
Amounts recognized in other comprehensive income (loss):
Prior service credit	$	85		$	93		$	—		$	—
Net actuarial (loss) gain	(3,010		)	(3,309		)	(16		)	(27		)
Total recognized accumulated other comprehensive (loss) income, December 31	$	(2,925	)	$	(3,216	)	$	(16	)	$	(27	)
Cumulative employer contributions in excess (deficient) of net periodic cost	3,565			2,949			(81		)	(80		)
Net asset (liability) recognized in consolidated balance sheet, December 31	$	640		$	(267	)	$	(97	)	$	(107	)
Accumulated benefit obligation, December 31	$	8,413		$	8,229		$	—		$	—

	Non-U.S. Pension Benefits						Non-U.S. Postretirement Benefits
(In millions of dollars)	2013			2012			2013		2012
Reconciliation of prior service credit (cost):
Beginning balance	$	93		$	23		$	—	$	1
Recognized as component of net periodic benefit credit	(6		)	(3		)	—		(1		)
Effect of curtailment	—			(1		)	—		—
Changes in plan assets and benefit obligations recognized in other comprehensive income:
Plan amendments	—			71			—		—
Exchange rate adjustments	(2		)	3			—		—
Prior service credit, December 31	$	85		$	93		$	—	$	—

	Non-U.S. Pension Benefits						Non-U.S. Postretirement Benefits
(In millions of dollars)	2013			2012			2013			2012
Reconciliation of net actuarial gain (loss):
Beginning balance	$	(3,309	)	$	(3,038	)	$	(27	)	$	(19	)
Recognized as component of net periodic benefit cost	108			118			2			1
Effect of settlement	—			1			—			—
Changes in plan assets and benefit obligations recognized in other comprehensive income (loss):
Liability experience	53			(419		)	8			(10		)
Asset experience	111			138			—			—
Effect of curtailment	—			3			—			1
Total amount recognized as change in plan assets and benefit obligations	164			(278		)	8			(9		)
Exchange rate adjustments	27			(112		)	1			—
Net actuarial gain (loss), December 31	$	(3,010	)	$	(3,309	)	$	(16	)	$	(27	)

For the Years Ended December 31,	Non-U.S. Pension Benefits							Non-U.S. Postretirement Benefits
(In millions of dollars)	2013			2012		2011		2013			2012		2011
Total recognized in net periodic benefit cost and other comprehensive (income) loss	$	(276	)	$	246	$	792	$	(2	)	$	16	$	12

The following schedules provide information concerning the Company’s U.S. defined benefit pension plans and postretirement benefit plans:

	U.S. Pension Benefits						U.S.  Postretirement Benefits
(In millions of dollars)	2013			2012			2013			2012
Change in benefit obligation:
Benefit obligation at beginning of year	$	5,197		$	4,533		$	176		$	162
Service cost	104			93			3			3
Interest cost	229			230			7			8
Plan combination	36			—			—			—
Actuarial (gain) loss	(547		)	522			(15		)	13
Medicare Part D subsidy	—			—			1			3
Benefits paid	(192		)	(181		)	(14		)	(13		)
Benefit obligation, December 31	$	4,827		$	5,197		$	158		$	176
Change in plan assets:
Fair value of plan assets at beginning of year	$	3,936		$	3,493		$	—		$	—
Plan combination	21			—			—			—
Actual return on plan assets	488			500			—			—
Employer contributions	26			124			13			10
Medicare Part D subsidy	—			—			1			3
Benefits paid	(192		)	(181		)	(14		)	(13		)
Fair value of plan assets, December 31	$	4,279		$	3,936		$	—		$	—
Net funded status, December 31	$	(548	)	$	(1,261	)	$	(158	)	$	(176	)
Amounts recognized in the consolidated balance sheets:
Current liabilities	$	(24	)	$	(25	)	$	(8	)	$	(9	)
Noncurrent liabilities	(524		)	(1,236		)	(150		)	(167		)
Net liability recognized, December 31	$	(548	)	$	(1,261	)	$	(158	)	$	(176	)
Amounts recognized in other comprehensive income (loss):
Prior service credit	$	7		$	23		$	—		$	—
Net actuarial (loss) gain	(974		)	(1,887		)	13			(2		)
Total recognized accumulated other comprehensive (loss) income, December 31	$	(967	)	$	(1,864	)	$	13		$	(2	)
Cumulative employer contributions in excess (deficient) of net periodic cost	419			603			(171		)	(174		)
Net amount recognized in consolidated balance sheet	$	(548	)	$	(1,261	)	$	(158	)	$	(176	)
Accumulated benefit obligation at December 31	$	4,753		$	5,114		$	—		$	—

	U.S. Pension Benefits						U.S.  Postretirement Benefits
(In millions of dollars)	2013			2012			2013		2012
Reconciliation of prior service credit (charge) recognized in accumulated other comprehensive income (loss):
Beginning balance	$	23		$	39		$	—	$	13
Recognized as component of net periodic benefit credit	(16		)	(16		)	—		(13		)
Prior service credit, December 31	$	7		$	23		$	—	$	—

Schedule of total recognized in net periodic benefit cost and other comprehensive income (loss)

	Non-U.S. Pension Benefits						Non-U.S. Postretirement Benefits
(In millions of dollars)	2013			2012			2013		2012
Reconciliation of prior service credit (cost):
Beginning balance	$	93		$	23		$	—	$	1
Recognized as component of net periodic benefit credit	(6		)	(3		)	—		(1		)
Effect of curtailment	—			(1		)	—		—
Changes in plan assets and benefit obligations recognized in other comprehensive income:
Plan amendments	—			71			—		—
Exchange rate adjustments	(2		)	3			—		—
Prior service credit, December 31	$	85		$	93		$	—	$	—

	U.S. Pension Benefits						U.S.  Postretirement Benefits
(In millions of dollars)	2013			2012			2013			2012
Reconciliation of net actuarial gain (loss) recognized in accumulated other comprehensive income (loss):
Beginning balance	$	(1,887	)	$	(1,695	)	$	(2	)	$	12
Recognized as component of net periodic benefit cost	208			152			—			(1		)
Changes in plan assets and benefit obligations recognized in other comprehensive income (loss):
Liability experience	541			(522		)	15			(13		)
Asset experience	164			178			—			—
Total gain (loss) recognized as change in plan assets and benefit obligations	705			(344		)	15			(13		)
Net actuarial gain (loss), December 31	$	(974	)	$	(1,887	)	$	13		$	(2	)

	Non-U.S. Pension Benefits						Non-U.S. Postretirement Benefits
(In millions of dollars)	2013			2012			2013			2012
Reconciliation of net actuarial gain (loss):
Beginning balance	$	(3,309	)	$	(3,038	)	$	(27	)	$	(19	)
Recognized as component of net periodic benefit cost	108			118			2			1
Effect of settlement	—			1			—			—
Changes in plan assets and benefit obligations recognized in other comprehensive income (loss):
Liability experience	53			(419		)	8			(10		)
Asset experience	111			138			—			—
Effect of curtailment	—			3			—			1
Total amount recognized as change in plan assets and benefit obligations	164			(278		)	8			(9		)
Exchange rate adjustments	27			(112		)	1			—
Net actuarial gain (loss), December 31	$	(3,010	)	$	(3,309	)	$	(16	)	$	(27	)

	U.S. Pension Benefits						U.S.  Postretirement Benefits
(In millions of dollars)	2013			2012			2013		2012
Reconciliation of prior service credit (charge) recognized in accumulated other comprehensive income (loss):
Beginning balance	$	23		$	39		$	—	$	13
Recognized as component of net periodic benefit credit	(16		)	(16		)	—		(13		)
Prior service credit, December 31	$	7		$	23		$	—	$	—

	U.S. Pension Benefits						U.S.  Postretirement Benefits
(In millions of dollars)	2013			2012			2013			2012
Reconciliation of net actuarial gain (loss) recognized in accumulated other comprehensive income (loss):
Beginning balance	$	(1,887	)	$	(1,695	)	$	(2	)	$	12
Recognized as component of net periodic benefit cost	208			152			—			(1		)
Changes in plan assets and benefit obligations recognized in other comprehensive income (loss):
Liability experience	541			(522		)	15			(13		)
Asset experience	164			178			—			—
Total gain (loss) recognized as change in plan assets and benefit obligations	705			(344		)	15			(13		)
Net actuarial gain (loss), December 31	$	(974	)	$	(1,887	)	$	13		$	(2	)

For the Years Ended December 31,	U.S. Pension Benefits							U.S. Postretirement Benefits
(In millions of dollars)	2013			2012		2011		2013			2012		2011
Total recognized in net periodic benefit cost and other comprehensive loss (income)	$	(696	)	$	346	$	467	$	(5	)	$	24	$	(9	)

Schedule of amounts recognized in other comprehensive income (loss)

For the Years Ended December 31,	Non-U.S. Pension Benefits							Non-U.S. Postretirement Benefits
(In millions of dollars)	2013			2012		2011		2013			2012		2011
Total recognized in net periodic benefit cost and other comprehensive (income) loss	$	(276	)	$	246	$	792	$	(2	)	$	16	$	12

For the Years Ended December 31,	U.S. Pension Benefits							U.S. Postretirement Benefits
(In millions of dollars)	2013			2012		2011		2013			2012		2011
Total recognized in net periodic benefit cost and other comprehensive loss (income)	$	(696	)	$	346	$	467	$	(5	)	$	24	$	(9	)

Schedule of change in assumed health care cost trend rates

A one percentage point change in assumed health care cost trend rates would have the following effects:

(In millions of dollars)	1 Percentage Point Increase		1 Percentage Point Decrease
Effect on total of service and interest cost components	$	—	$	—
Effect on postretirement benefit obligation	$	2	$	(7	)

A one percentage point change in assumed health care cost trend rates would have the following effects:

(In millions of dollars)	1 Percentage Point Increase		1 Percentage Point Decrease
Effect on total of service and interest cost components	$	1	$	(1	)
Effect on postretirement benefit obligation	$	10	$	(8	)

Schedule of estimated amounts that will be amortized from accumulated other comprehensive in the next fiscal year

Estimated amounts that will be amortized from accumulated other comprehensive income in the next fiscal year:

	Non-U.S. Pension Benefits			Non-U.S. Postretirement Benefits
(In millions of dollars)	2014			2014
Prior service credit	$	(6	)	$	—
Net actuarial loss	95			1
Projected cost	$	89		$	1

Estimated amounts that will be amortized from accumulated other comprehensive income in the next fiscal year:

	U.S. Pension Benefits			U.S. Postretirement Benefits
(In millions of dollars)	2014			2014
Prior service credit	$	(7	)	$	—
Net actuarial loss	105			1
Projected cost	$	98		$	1

Schedule of estimated future benefit payments for its pension and postretirement benefits

The Plans' estimated future benefit payments for its pension and postretirement benefits (without reduction for Medicare subsidy receipts) are as follows:

For the Years Ended December 31,	Pension Benefits				Postretirement Benefits
(In millions of dollars)	U.S.		Non-U.S.		U.S.		Non-U.S.
2014	$	207	$	287	$	11	$	4
2015	$	219	$	299	$	11	$	4
2016	$	233	$	318	$	11	$	5
2017	$	244	$	342	$	11	$	5
2018	$	255	$	350	$	11	$	5
2019-2023	$	1,424	$	2,046	$	57	$	27

Summary of the U.S. and non-U.S. plans investments measured at fair value on a recurring basis

The following table sets forth, by level within the fair value hierarchy, a summary of the U.S. and non-U.S. plans investments measured at fair value on a recurring basis at December 31, 2013 and 2012.

	Fair Value Measurements at December 31, 2013
Assets (In millions of dollars)	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Common/Collective trusts	$	138	$	5,649	$	151	$	5,938
Corporate obligations	—		2,330		4		2,334
Corporate stocks	2,434		5		1		2,440
Private equity/partnerships	—		2		799		801
Government securities	10		340		2		352
Real estate	—		7		312		319
Short-term investment funds	824		15		—		839
Company common stock	261		—		—		261
Other investments	35		3		238		276
Insurance group annuity contracts	—		—		—		—
Swaps	—		2		—		2
Total investments	$	3,702	$	8,353	$	1,507	$	13,562

	Fair Value Measurements at December 31, 2012
Assets (In millions of dollars)	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Common/Collective trusts	$	16	$	5,376	$	—	$	5,392
Corporate obligations	—		2,236		1		2,237
Corporate stocks	2,005		4		9		2,018
Private equity/partnerships	2		2		824		828
Government securities	9		309		—		318
Real estate	11		8		357		376
Short-term investment funds	410		4		—		414
Company common stock	276		—		—		276
Other investments	11		112		216		339
Insurance group annuity contracts	—		—		23		23
Swaps	—		4		—		4
Total investments	$	2,740	$	8,055	$	1,430	$	12,225

Summary of changes in the fair value of the plans' Level 3 assets

The tables below set forth a summary of changes in the fair value of the plans’ Level 3 assets for the years ended December 31, 2013 and December 31, 2012:

Assets (In millions)	Fair Value, January 1, 2013		Purchases		Sales			Unrealized Gain/ (Loss)			Realized Gain/ (Loss)		Exchange Rate Impact			Transfers in/(out) and Other			Fair Value, December 31, 2013
Private equity/Partnerships	$	824	$	146	$	(174	)	$	(155	)	$	150	$	(1	)	$	9		$	799
Real estate	357		21		(95		)	6			26		(3		)	—			312
Other investments	216		18		(13		)	11			—		6			—			238
Common/Collective Trusts	—		61		—			(4		)	—		(5		)	99			151
Insurance group annuity contracts	23		—		—			(1		)	—		—			(22		)	—
Corporate stocks	9		—		—			—			—		—			(8		)	1
Corporate obligations	1		1		—			—			—		—			2			4
Government Securities	—		—		—			(1		)	—		—			3			2
Total assets	$	1,430	$	247	$	(282	)	$	(144	)	$	176	$	(3	)	$	83		$	1,507

Assets (In millions)	Fair Value, January 1, 2012		Purchases		Sales			Unrealized Gain/ (Loss)		Realized Gain/ (Loss)			Exchange Rate Impact		Transfers in/(out) and Other		Fair Value, December 31, 2012
Private equity/Partnerships	$	779	$	86	$	(79	)	$	138	$	(113	)	$	13	$	—	$	824
Real estate	319		11		(3		)	104		(86		)	12		—		357
Other investments	202		17		(24		)	11		6			4		—		216
Insurance group annuity contracts	20		160		(157		)	1		(1		)	—		—		23
Corporate stocks	8		1		—			—		—			—		—		9
Corporate obligations	1		—		—			—		—			—		—		1
Total assets	$	1,329	$	275	$	(263	)	$	254	$	(194	)	$	29	$	—	$	1,430