Pension and Postretirement Plans (Narrative) (Details) (USD $)	6 Months Ended		3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended	3 Months Ended				6 Months Ended					6 Months Ended			6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Pension Plan [Member] companies	Jun. 30, 2012 Pension Plan [Member]	Jun. 30, 2013 Pension Plan [Member] companies	Jun. 30, 2012 Pension Plan [Member]	Dec. 31, 2012 Pension Plan [Member]	Jun. 30, 2013 Pension Plan [Member] Washington Post Newspaper [Member] Voluntary Retirement Incentive Program [Member]	Mar. 31, 2013 Pension Plan [Member] Washington Post Newspaper [Member] Voluntary Retirement Incentive Program [Member]	Jun. 30, 2013 Pension Plan [Member] Washington Post Newspaper [Member] Voluntary Retirement Incentive Program [Member]	Mar. 31, 2013 Pension Plan [Member] Washington Post Newspaper [Member] special separation benefits [Member]	Mar. 31, 2012 Pension Plan [Member] Post-Newsweek Media [Member] Voluntary Retirement Incentive Program [Member]	Jun. 30, 2013 Other Postretirement Plans [Member]	Jun. 30, 2012 Other Postretirement Plans [Member]	Jun. 30, 2013 Other Postretirement Plans [Member]	Jun. 30, 2012 Other Postretirement Plans [Member]	Jun. 30, 2013 Other Postretirement Plans [Member] Daily Herald [Member]	Jun. 30, 2013 Berkshire Hathaway Common Stock [Member] Pension Plan [Member]	Dec. 31, 2012 Berkshire Hathaway Common Stock [Member] Pension Plan [Member]	Jun. 30, 2013 Foreign Investments [Member] Pension Plan [Member]	Jun. 30, 2013 Single Equity Concentration [Member] Pension Plan [Member] companies	Dec. 31, 2012 Single Equity Concentration [Member] Pension Plan [Member] companies	Jun. 30, 2013 Concentration In Single Entity, Type Of Industry, Foreign Country Or Individual Fund [Member] Pension Plan [Member]	Jun. 30, 2013 Fixed income securities [Member] Pension Plan [Member]	Jun. 30, 2013 Geographic Concentration [Member] Foreign Investments [Member] Pension Plan [Member] country	Dec. 31, 2012 Geographic Concentration [Member] Foreign Investments [Member] Pension Plan [Member] country
Retirement Benefits Disclosure [Line Items]
Early retirement program expense	$ 22,700,000	$ 1,022,000	$ 8,442,000	$ 0	$ 22,700,000	$ 1,022,000		$ 8,400,000	$ 12,000,000	$ 20,400,000	$ 2,300,000	$ 1,000,000
Number of investment companies actively managing plan assets			2		2
Defined benefit plan, target allocation maximum percentage of assets, equity securities																				24.00%
Defined benefit plan, target allocation maximum percentage of assets, singular equity security, without prior approval by plan administrator																		20.00%			10.00%
Defined benefit plan, target allocation percentage of assets, fixed-income securities, range minimum																								10.00%
Minimum percentage of plan assets considered as significant concentrations in pension plans																							10.00%
Amount of plan assets managed internally by the company			None		None
Settlement gain													0	0	(3,471,000)	0	(3,500,000)
Value of investments																					321,200,000	223,100,000			337,400,000	240,400,000
Percentage of total plan assets			100.00%		100.00%		100.00%														14.00%	11.00%			14.00%	12.00%
Value of related party investments																		$ 226,200,000	$ 179,900,000
Number of investments the company's pension plan held which individually exceed 10% of total plan assets																					1	1
Number of foreign countries for which the companys pension plan holds investments that exceed 10% of total plan assets																									1	1