Employment Benefit Plans Other Details (Details) (USD $) In Millions, unless otherwise specified	11 Months Ended	12 Months Ended		1 Months Ended
	Dec. 31, 2010 Successor [Member]	Dec. 31, 2012 Successor [Member]	Dec. 31, 2011 Successor [Member]	Feb. 12, 2010 Predecessor [Member]	Dec. 31, 2012 Funded Pension Plan [Member] Successor [Member] Pension Plans, Defined Benefit [Member]	Dec. 31, 2012 Unfunded Non-Qualified Pension Plan [Member] Successor [Member] Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Description of 401(k) plans and non-qualified defined contribution plan		BNSF sponsors qualified 401(k) plans that cover substantially all employees and a non-qualified defined contribution plan that covers certain officers and other employees. BNSF matches 50 percent of the first six percent of non-union employees’ contributions and matches 25 percent on the first four percent of a limited number of union employees’ contributions, which are subject to certain percentage limits of the employees’ earnings, at each pay period. Non-union employees are eligible to receive an annual discretionary matching contribution of up to 30 percent of the first six percent of their contributions. Employer contributions are subject to a five-year length of service vesting schedule.
401(k) matching expense	$ 25	$ 32	$ 31	$ 3
Collective bargaining agreements description		Under collective bargaining agreements, BNSF participates in multi-employer benefit plans that provide certain postretirement health care and life insurance benefits for eligible union employees.
Multiemployer Plan, insurance premiums	55	71	73	8
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year					$ 9	$ 7
Average number of employees covered under multi-employer benefit plans	33,000	36,000	35,000	31,000