Reinsurance - Effective Exit of GMDB and GMIB Business (Details) (USD $)	12 Months Ended			3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2013	Feb. 04, 2013
Ceded Credit Risk [Line Items]
Reinsurance preimums paid	$ 0	$ 2,196,000,000	$ 0
Other Revenues [Member] | Variable Annuity [Member] | Guaranteed Minimum Death Benefit [Member]
Ceded Credit Risk [Line Items]
Derivative Gain (Loss)		(32,000,000)	(105,000,000)
Berkshire Hathway Life Insurance Company Of Nebraska [Member] | Variable Annuity [Member]
Ceded Credit Risk [Line Items]
Percent of future claim payments reinsured					100.00%
Ceded Reinsurance Agreement, Coverage Limit, Amount Remaining	3,700,000,000
Ceded Reinsurance Agreement Charge, After-tax				507,000,000
Ceded Reinsurance Agreement Charge, Pre-tax				781,000,000
Reinsurance preimums paid				2,200,000,000
Berkshire Hathway Life Insurance Company Of Nebraska [Member] | Variable Annuity [Member] | Guaranteed Minimum Death Benefit [Member]
Ceded Credit Risk [Line Items]
Reinsurance preimums paid				1,647,000,000
Berkshire Hathway Life Insurance Company Of Nebraska [Member] | Other Benefits Expense [Member] | Variable Annuity [Member]
Ceded Credit Risk [Line Items]
Ceded Reinsurance Agreement Charge, Pre-tax				727,000,000
Berkshire Hathway Life Insurance Company Of Nebraska [Member] | Guaranteed Minimum Income Benefits Fair Value Gain Loss [Member] | Variable Annuity [Member]
Ceded Credit Risk [Line Items]
Ceded Reinsurance Agreement Charge, Pre-tax				45,000,000
Berkshire Hathway Life Insurance Company Of Nebraska [Member] | Other Operating Expenses [Member] | Variable Annuity [Member]
Ceded Credit Risk [Line Items]
Ceded Reinsurance Agreement Charge, Pre-tax				$ 9,000,000