Retirement Plans (Tables)

12 Months Ended

Dec. 31, 2016

Compensation And Retirement Disclosure [Abstract]

Change in Benefit Obligation, Fair Value of Plan Assets, and Funded Status of Pension Plans and Postretirement Medical Plan

The following table summarizes the benefit obligations, the fair value of plan assets, and the funded status of our pension and postretirement medical plans:

	Funded						Unfunded						Postretirement
	Pension Plans						Pension Plan						Medical Plan
	2016			2015			2016			2015			2016			2015
	(In millions)
Change In Benefit Obligation
Balance at January 1	$	2,321		$	2,450		$	259		$	278		$	98		$	94
Service cost		44			51			16			16			4			4
Interest cost		98			93			9			9			3			3
Actuarial loss (gain) (a)		162			(156	)		(5	)		(2	)		(13	)		5
Benefit payments (b)		(132	)		(85	)		(23	)		(42	)		(8	)		(8	)
Plan curtailments		(2	)		(4	)		—			—			—			—
Special termination benefits		1			1			—			—			—			—
Assumption of HOVENSA pension plan		151			—			—			—			—			—
Foreign currency exchange rate changes		(83	)		(29	)		—			—			—			—
Balance at December 31		2,560			2,321			256			259			84			98
Change In Fair Value of Plan Assets
Balance at January 1	$	2,206		$	2,251		$	—		$	—		$	—		$	—
Actual return on plan assets		153			28			—			—			—			—
Employer contributions		26			44			23			42			8			8
Benefit payments (b)		(132	)		(85	)		(23	)		(42	)		(8	)		(8	)
Assumption of HOVENSA pension plan		126			—			—			—			—			—
Foreign currency exchange rate changes		(95	)		(32	)		—			—			—			—
Balance at December 31		2,284			2,206			—			—			—			—
Funded Status (Plan assets greater (less) than benefit obligations) at December 31	$	(276	)	$	(115	)	$	(256	)	$	(259	)	$	(84	)	$	(98	)
Unrecognized Net Actuarial (Gains) Losses	$	895		$	775		$	93		$	105		$	(13	)	$	—

(a) The change in discount rate in 2016 resulted in total actuarial losses of approximately $175 million.

(b) Benefit payments include lump-sum settlement payments of $65 million in 2016 (2015: $41 million).

Pension Plans and Postretirement Medical Plan Amounts Recognized in Consolidated Balance Sheet

  Amounts recognized in the Consolidated Balance Sheet at December 31 consisted of the following:

	Funded						Unfunded						Postretirement
	Pension Plans						Pension Plan						Medical Plan
	2016			2015			2016			2015			2016			2015
	(In millions)
Pension asset / (accrued benefit liability)	$	(276	)	$	(115	)	$	(256	)	$	(259	)	$	(84	)	$	(98	)
Accumulated other comprehensive loss, pre-tax (a)		895			775			93			105			(13	)		—

(a) The after‑tax deficit reflected in Accumulated other comprehensive income (loss) was $660 million at December 31, 2016 (2015: $563 million deficit).

Components of Net Periodic Benefit Cost for Funded and Unfunded Pension Plans and Postretirement Medical Plan

The net periodic benefit cost for funded and unfunded pension plans, and the postretirement medical plan, is as follows:

	Pension Plans									Postretirement Medical Plan
	2016			2015			2014			2016		2015		2014
	(In millions)
Service cost	$	60		$	67		$	57		$	4	$	4	$	4
Interest cost		107			102			100			3		3		3
Expected return on plan assets		(166	)		(168	)		(161	)		—		—		—
Amortization of unrecognized net actuarial losses		60			75			32			—		—		—
Settlement loss		—			17			24			—		—		—
Special termination benefit recognized		1			1			1			—		—		—
Net Periodic Benefit Cost	$	62		$	94		$	53		$	7	$	7	$	7

Actuarial Assumptions Used For Pension Plans & Postretirement Medical Plan

The weighted average actuarial assumptions used for funded and unfunded pension plans were as follows:

	2016			2015			2014
Weighted Average Assumptions Used to Determine Benefit Obligations at December 31
Discount rate		3.7	%		4.1	%		3.8	%
Rate of compensation increase		4.6	%		4.5	%		5.0	%
Weighted Average Assumptions Used to Determine Net Periodic Benefit Cost for the Years Ended December 31
Discount rate		4.1	%		3.8	%		4.6	%
Expected return on plan assets		7.4	%		7.5	%		7.5	%
Rate of compensation increase		4.5	%		5.0	%		4.4	%

The actuarial assumptions used for postretirement medical plan, as follows:

	2016			2015			2014
Assumptions Used to Determine Benefit Obligations at December 31
Discount rate		3.5	%		3.5	%		3.1	%
Initial health care trend rate		7.7	%		6.7	%		6.8	%
Ultimate trend rate		4.5	%		4.5	%		4.5	%
Year in which ultimate trend rate is reached		2038			2038			2029

Fair Value of Financial Assets of Funded Pension Plans

The following tables provide the fair value of the financial assets of the funded pension plans as of December 31, 2016 and 2015 in accordance with the fair value measurement hierarchy described in Note 1, Nature of Operations, Basis of Presentation and Summary of Accounting Policies.

	Level 1		Level 2		Level 3		Total
	(In millions)
December 31, 2016
Cash and Short-Term Investment Funds	$	9	$	79	$	—	$	88
Equities:
U.S. equities (domestic)		550		—		—		550
International equities (non-U.S.)		160		275		—		435
Global equities (domestic and non-U.S.)		2		197		—		199
Fixed Income:
Treasury and government issued (a)		—		202		—		202
Government related (b)		—		38		—		38
Mortgage-backed securities (c)		—		164		2		166
Corporate		1		186		—		187
Other:
Hedge funds		—		—		209		209
Private equity funds		—		—		126		126
Real estate funds		10		—		52		62
Diversified commodities funds		—		22		—		22
	$	732	$	1,163	$	389	$	2,284
December 31, 2015
Cash and Short-Term Investment Funds	$	—	$	34	$	—	$	34
Equities:
U.S. equities (domestic)		556		—		—		556
International equities (non-U.S.)		159		266		—		425
Global equities (domestic and non-U.S.)		2		217		—		219
Fixed Income:
Treasury and government issued (a)		—		213		—		213
Government related (b)		—		6		1		7
Mortgage-backed securities (c)		—		174		2		176
Corporate		—		157		—		157
Other:
Hedge funds		—		—		216		216
Private equity funds		—		—		122		122
Real estate funds		12		—		52		64
Diversified commodities funds		—		17		—		17
	$	729	$	1,084	$	393	$	2,206

(a) Includes securities issued and guaranteed by U.S. and non‑U.S. governments.

(b) Primarily consists of securities issued by governmental agencies and municipalities.

(c) Comprised of U.S. residential and commercial mortgage-backed securities.

Changes in Financial Assets that are Measured at Fair Value Based on Level 3 Inputs that are held by Institutional Funds

The following tables provide changes in financial assets that are measured at fair value based on Level 3 inputs that are held by institutional funds classified as:

							Private			Real
	Fixed			Hedge			Equity			Estate
	Income			Funds			Funds			Funds			Total
	(In millions)
Balance at January 1, 2015	$	2		$	302		$	105		$	48		$	457
Actual return on plan assets		—			(5	)		18			9			22
Purchases, sales or other settlements		1			(81	)		(1	)		(5	)		(86	)
Net transfers in (out) of Level 3		—			—			—			—			—
Balance at December 31, 2015		3			216			122			52			393
Actual return on plan assets		—			(7	)		5			7			5
Purchases, sales or other settlements		(1	)		—			(1	)		(7	)		(9	)
Net transfers in (out) of Level 3		—			—			—			—			—
Balance at December 31, 2016	$	2		$	209		$	126		$	52		$	389

Estimated Future Benefit Payments for Funded and Unfunded Pension Plans and Postretirement Medical Plan

Estimated future benefit payments by the funded and unfunded pension plans, and the postretirement medical plan, which reflect expected future service, are as follows (in millions):

2017	$	138
2018		123
2019		133
2020		135
2021		136
Years 2022 to 2026		725