Employment Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2015

Defined Benefit Plan Disclosure [Line Items]

Components of the net (benefit) cost for certain employee benefit plans were as follows (in millions):



	Pension Benefits
	Year Ended			Year Ended			Year Ended
	December 31, 2015			December 31, 2014			December 31, 2013
Service cost	$	48		$	38		$	47
Interest cost	90			95			89
Expected return on plan assets	(138		)	(134		)	(124		)
Amortization of prior service credits	(1		)	(1		)	—
Amortization of net loss	2			1			17
Settlements	(1		)	(1		)	(1		)
Net (benefit) cost recognized	$	—		$	(2	)	$	28



	Retiree Health and Welfare Benefits
	Year Ended			Year Ended			Year Ended
	December 31, 2015			December 31, 2014			December 31, 2013
Service cost	$	1		$	1		$	1
Interest cost	10			11			12
Amortization of prior service credits	(2		)	(2		)	(1		)
Amortization of net loss	2			1			5
Net cost recognized	$	11		$	11		$	17

Schedule of Net Funded Status [Table Text Block]

The following table shows the change in projected benefit obligation (in millions):



	Pension Benefits
Change in Benefit Obligation	December 31, 2015			December 31, 2014
Projected benefit obligation at beginning of period	$	2,452		$	2,220
Service cost	48			38
Interest cost	90			95
Actuarial loss (gain)	(111		)	256
Benefits paid	(145		)	(141		)
Administrative expenses	(1		)	(1		)
Settlements	(13		)	(15		)
Projected benefit obligation at end of period	2,320			2,452
Component representing future salary increases	(146		)	(146		)
Accumulated benefit obligation at end of period	$	2,174		$	2,306



	Retiree Health and Welfare Benefits
Change in Benefit Obligation	December 31, 2015			December 31, 2014
Projected benefit obligation at beginning of period	$	280		$	272
Service cost	1			1
Interest cost	10			11
Plan participants’ contributions	5			6
Actuarial loss (gain)	(13		)	13
Benefits paid	(25		)	(23		)
Projected benefit obligation at end of period	$	258		$	280

BNSF’s pension plans had plan assets in excess of accumulated benefit obligations and projected benefit obligations in excess of plan assets at December 31, 2015 and December 31, 2014.

The following tables show the change in plan assets of the plans (in millions):



	Pension Benefits
Change in Plan Assets	December 31, 2015			December 31, 2014
Fair value of plan assets at beginning of period	$	2,342		$	2,490
Actual return on plan assets	95			(3		)
Employer contributions^a	11			12
Benefits paid	(145		)	(141		)
Administrative expenses	(1		)	(1		)
Settlements	(13		)	(15		)
Fair value of plan assets at measurement date	$	2,289		$	2,342

^aOther than contributions to the BNSF Retirement Plan, employer contributions were classified as Other, Net under Operating Activities in the Company’s Consolidated Statements of Cash Flows.



	Retiree Health and Welfare Benefits
Change in Plan Assets	December 31, 2015			December 31, 2014
Fair value of plan assets at beginning of period	$	—		$	—
Employer contributions^a	20			17
Plan participants’ contributions	5			6
Benefits paid	(25		)	(23		)
Fair value of plan assets at measurement date	$	—		$	—

^a Employer contributions were classified as Other, Net under Operating Activities in the Company’s Consolidated Statements of Cash Flows.

The following table shows the funded status, defined as plan assets less the projected benefit obligation (in millions):



	Pension Benefits						Retiree Health and Welfare Benefits
	December 31, 2015			December 31, 2014			December 31, 2015			December 31, 2014
Funded status (plan assets less projected benefit obligations)	$	(31	)	$	(110	)	$	(258	)	$	(280	)

Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]

The following table shows the pre-tax change in AOCI attributable to the components of the net cost and the change in benefit obligation (in millions):



	Pension Benefits
	Year Ended			Year Ended			Year Ended
Change in AOCI	December 31, 2015			December 31, 2014			December 31, 2013
Beginning balance	$	34		$	427		$	(330	)
Amortization of net loss	2			1			17
Amortization of prior service credits	(1		)	(1		)	—
Prior service credits	—			—			7
Actuarial (loss) gain	68			(392		)	734
Settlements	(1		)	(1		)	(1		)
Ending balance	$	102		$	34		$	427



	Retiree Health and Welfare Benefits
	Year Ended			Year Ended			Year Ended
Change in AOCI	December 31, 2015			December 31, 2014			December 31, 2013
Beginning balance	$	(34	)	$	(20	)	$	(60	)
Amortization of net loss	2			1			5
Amortization of prior service credits	(2		)	(2		)	(1		)
Prior service credits	—			—			7
Actuarial (loss) gain	13			(13		)	29
Ending balance	$	(21	)	$	(34	)	$	(20	)

Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]

Pre-tax amounts currently recognized in AOCI consist of the following (in millions):



	Pension Benefits						Retiree Health and Welfare Benefits
	2015			2014			2015			2014
Net gain (loss)	$	99		$	29		$	(28	)	$	(43	)
Prior service credits	5			6			7			9
Settlements	(2		)	(1		)	—			—
Pre-tax amount recognized in AOCI at December 31,	$	102		$	34		$	(21	)	$	(34	)
After-tax amount recognized in AOCI at December 31,	$	63		$	21		$	(13	)	$	(21	)

Schedule of Assumptions Used [Table Text Block]

The assumptions used in accounting for the BNSF plans were as follows:



	Pension Benefits
	Year Ended		Year Ended		Year Ended
Assumptions Used to Determine Net Cost	December 31, 2015		December 31, 2014		December 31, 2013
Discount rate	3.79	%	4.50	%	3.75	%
Expected long-term rate of return on plan assets	6.60	%	6.75	%	6.75	%
Rate of compensation increase	3.80	%	3.80	%	3.80	%



	Retiree Health and Welfare Benefits
	Year Ended		Year Ended		Year Ended
Assumptions Used to Determine Net Cost	December 31, 2015		December 31, 2014		December 31, 2013
Discount rate	3.69	%	4.50	%	3.75	%
Rate of compensation increase	3.80	%	3.80	%	3.80	%



	Pension Benefits				Retiree Health and Welfare Benefits
Assumptions Used to Determine Benefit Obligations	December 31, 2015		December 31, 2014		December 31, 2015		December 31, 2014
Discount rate	4.22	%	3.79	%	4.09	%	3.69	%
Rate of compensation increase	3.80	%	3.80	%	3.80	%	3.80	%

Sensitivity analysis of impact on future net benefit cost resulting from hypothetical change in assumptions [Text Block]

The following table is an estimate of the impact on future net benefit cost that could result from hypothetical changes to the most sensitive assumptions, the discount rate and rate of return on plan assets:



Sensitivity Analysis
	Change in Net Benefit Cost
Hypothetical Discount Rate Change	Pension				Retiree Health and Welfare
50 basis point decrease	$	1	million	increase	$	1	million	increase
50 basis point increase	$	1	million	decrease	$	1	million	decrease
Hypothetical Rate of Return on Plan Assets Change	Pension
50 basis point decrease	$	11	million	increase
50 basis point increase	$	11	million	decrease

Schedule of Health Care Cost Trend Rates [Table Text Block]

The following table presents assumed health care cost trend rates:



	Year Ended		Year Ended		Year Ended
	December 31, 2015		December 31, 2014		December 31, 2013
Assumed health care cost trend rate for next year (participants over 65)^a	3.00	%	3.00	%	3.00	%
Assumed health care cost trend rate for next year (participants under 65)	7.70	%	7.90	%	8.20	%
Rate to which health care cost trend rate for participants under 65 is expected to decline and remain	4.50	%	4.50	%	4.50	%
Year that the rate reaches the ultimate trend rate	2038		2028		2028

^a Effective January 1, 2013, Medicare-eligible retirees who are enrolled in the retiree medical program received a contribution to a Health Reimbursement Account, which can be used to reimburse plan participants for health insurance premiums and to pay eligible out-of-pocket expenses.

Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates [Table Text Block]

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



	One Percentage- Point Increase		One Percentage- Point Decrease
Effect on total service and interest cost	$	1	$	(1	)
Effect on postretirement benefit obligation	$	19	$	(16	)

Schedule of Allocation of Plan Assets [Table Text Block]

The following table summarizes the investments of BNSF’s funded pension plans as of December 31, 2015, based on the inputs used to value them (in millions):



	Total as of
Asset Category	December 31, 2015		Level 1 Inputs ^a		Level 2 Inputs ^a		Level 3 Inputs ^a
Equity securities:^b
U.S.	$	2,001	$	2,001	$	—	$	—
International	59		59		—		—
Corporate debt securities	28		—		28		—
Registered investment companies	19		19		—		—
U.S. government debt securities	12		—		12		—
Collateralized obligations and mortgage backed securities (MBS)	3		—		3		—
Cash and cash equivalents	167		3		164		—
Total^c	$	2,289	$	2,082	$	207	$	—

^aSee Note 2 to the Consolidated Financial Statements under the heading “Fair Value Measurements” for a definition of each of these levels of inputs.

^bAs of December 31, 2015, three equity securities each exceeded 10 percent of total plan assets. These investments represent approximately 47 percent of total plan assets.

^c Excludes less than $1 million accrued for dividend and interest receivable.

Comparative Prior Year Information

The following table summarizes the investments of BNSF’s funded pension plans as of December 31, 2014, based on the inputs used to value them (in millions):



	Total as of
Asset Category	December 31, 2014		Level 1 Inputs ^a		Level 2 Inputs^a		Level 3 Inputs ^a
Equity securities:^b
U.S.	$	2,091	$	2,091	$	—	$	—
International	77		77		—		—
Corporate debt securities	30		—		30		—
Registered investment companies	28		28		—		—
U.S. government debt securities	13		—		13		—
Collateralized obligations and mortgage backed securities (MBS)	6		—		6		—
Cash and cash equivalents	97		—		97		—
Total ^c	$	2,342	$	2,196	$	146	$	—

^aSee Note 2 to the Consolidated Financial Statements under the heading “Fair Value Measurements” for a definition of each of these levels of inputs.

^bAs of December 31, 2014, three equity securities each exceeded 10 percent of total plan assets. These investments represented approximately 43 percent of total plan assets.

^cExcludes less than $1 million accrued for dividend and interest receivable.

Schedule of Expected Benefit Payments Years 2015 - 2024 [Table Text Block]

The following table shows expected benefit payments from its defined benefit pension plans and expected claim payments for the retiree health and welfare plan for the next five fiscal years and the aggregate five years thereafter (in millions):



Fiscal year	Expected Pension Plan Benefit Payments		^a	Expected Retiree Health and Welfare Payments
2016	$	168		$	21
2017	$	156		$	20
2018	$	155		$	20
2019	$	153		$	19
2020	$	151		$	18
2021-2025	$	693		$	81

^aPrimarily consists of the BNSF Retirement Plan payments, which are made from the plan trust and do not represent an immediate cash outflow to the Company.