Schedule IV - Reinsurance (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Life reinsurance in force:
Gross amount, life reinsurance in force	$ 0	[1]	$ 0	[1]	$ 0	[1]
Ceded to other companies, life reinsurance in force	46,947,677	[1]	378,391	[1]	443,798	[1]
Assumed from other companies, life reinsurance in force	68,854,340	[1]	77,917,632	[1]	82,099,647	[1]
Net amount, life reinsurance in force	21,906,663	[1]	77,539,241	[1]	81,655,849	[1]
Percentage of amount assumed to net, life reinsurance in force	314.30%	[1]	100.50%	[1]	100.50%	[1]
Total premiums earned:
Gross amount, premiums earned	5,173,403		4,966,207		4,604,323
Ceded to other companies, premiums earned	1,955,098		1,344,289		1,263,157
Assumed from other companies, premiums earned	2,676,765		2,687,603		2,749,271
Net amount, premiums earned	5,895,070		6,309,521		6,090,437
Percentage of amount assumed to net	45.40%		42.60%		45.10%
Property and casualty operations
Total premiums earned:
Gross amount, premiums earned	5,173,403		4,966,207		4,604,323
Ceded to other companies, premiums earned	1,799,294		1,315,369		1,231,835
Assumed from other companies, premiums earned	2,343,329		2,363,261		2,393,490
Net amount, premiums earned	5,717,438		6,014,099		5,765,978
Percentage of amount assumed to net	41.00%		39.30%		41.50%
Life operations
Total premiums earned:
Gross amount, premiums earned	0		0		0
Ceded to other companies, premiums earned	155,804		28,920		31,322
Assumed from other companies, premiums earned	333,436		324,342		355,781
Net amount, premiums earned	$ 177,632		$ 295,422		$ 324,459
Percentage of amount assumed to net	187.70%		109.80%		109.70%

[1] Represents the sum face value outstanding of the in force life reinsurance policies.