Reinsurance - Effective Exit of GMDB and GMIB Business (Details) (USD $)	9 Months Ended			3 Months Ended	12 Months Ended		3 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2013 Other Revenues [Member] Variable Annuity [Member] Guaranteed Minimum Death Benefit [Member] Interest And Equity Hedge [Member]	Mar. 31, 2013 Berkshire Hathway Life Insurance Company Of Nebraska [Member] Variable Annuity [Member]	Dec. 31, 2013 Berkshire Hathway Life Insurance Company Of Nebraska [Member] Variable Annuity [Member]	Feb. 04, 2013 Berkshire Hathway Life Insurance Company Of Nebraska [Member] Variable Annuity [Member]	Mar. 31, 2013 Berkshire Hathway Life Insurance Company Of Nebraska [Member] Other Benefits Expense [Member] Variable Annuity [Member]	Mar. 31, 2013 Berkshire Hathway Life Insurance Company Of Nebraska [Member] Guaranteed Minimum Income Benefits Fair Value Gain Loss [Member] Variable Annuity [Member]	Mar. 31, 2013 Berkshire Hathway Life Insurance Company Of Nebraska [Member] Other Operating Expenses [Member] Variable Annuity [Member]
Ceded Credit Risk [Line Items]
Percent of future claim payments reinsured						100.00%
Ceded Reinsurance Agreement, Coverage Limit, Fixed Portion						$ 3,800,000,000
Ceded Reinsurance Agreement Charge, After-tax				507,000,000
Ceded Reinsurance Agreement Charge, Pre-tax				781,000,000			727,000,000	45,000,000	9,000,000
Reinsurance preimums paid	0	2,196,000,000		2,196,000,000	1,647,000,000
Derivative Gain (Loss)			$ (32,000,000)