CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash Flows from Operating Activities:
Net income	$ 634,970	$ 605,803
Change in operating assets and liabilities:
Accrued investment income	(40,160)	23,473
Premiums receivable and other reinsurance balances	182,018	(519,107)
Deferred policy acquisition costs	(130,305)	23,682
Reinsurance ceded receivable balances	(124,290)	37,468
Future policy benefits, other policy claims and benefits, and other reinsurance balances	1,174,427	920,492
Deferred income taxes	200,653	(8,136)
Other assets and other liabilities, net	(253,405)	(47,978)
Amortization of net investment premiums, discounts and other	(44,386)	(55,154)
Depreciation, Depletion and Amortization	33,624	32,153
Investment related (gains) losses, net	(69,044)	31,059
Other, net	199,148	56,408
Net cash provided by operating activities	1,763,250	1,100,163
Cash Flows from Investing Activities:
Sales of fixed maturity securities available-for-sale	10,544,915	6,314,968
Maturities of fixed maturity securities available-for-sale	614,489	461,764
Proceeds from Sale of Available-for-sale Securities, Equity	35,840	44,952
Payments to Acquire Debt Securities, Available-for-sale	11,377,473	6,041,665
Payments to Acquire Available-for-sale Securities, Equity	(77,553)	(12,578)
Payments to Acquire Mortgage Notes Receivable	(986,709)	(671,956)
Proceeds from Sale and Collection of Mortgage Notes Receivable	308,694	290,450
Proceeds from Collection of Policy Loans	73,705	43,995
Payments for (Proceeds from) Policy Loans	4,942	6,422
Increase (Decrease) in Funds Held under Reinsurance Agreements	51,623	61,969
Payments to Acquire Businesses, Net of Cash Acquired	3,561	(31,441)
Payments to Acquire Property, Plant, and Equipment	(23,967)	(20,478)
Change in short-term investments	154,332	34,856
Change in other invested assets	(193,475)	(313,464)
Net cash provided by (used in) investing activities	(980,206)	31,012
Cash Flows from Financing Activities:
Dividends to stockholders	(119,233)	(102,441)
Proceeds from (Repayments of) Secured Debt	(76,516)	(75,146)
Payments of Debt Issuance Costs	(4,750)	0
Proceeds from Issuance of Long-term Debt	598,524	0
Repayments of Long-term Debt	(2,091)	(2,007)
Purchases of treasury stock	(98,231)	(273,873)
Exercise of stock options, net	4,259	2,336
Change in cash collateral for derivative positions and other arrangements	(67,069)	(21,288)
Deposits on universal life and other investment type policies and contracts	318,510	320,871
Withdrawals on universal life and other investment type policies and contracts	(572,996)	(520,649)
Net cash used in financing activities	(19,593)	(672,197)
Effect of exchange rate changes on cash	(17,588)	(32,013)
Change in cash and cash equivalents	745,863	426,965
Cash and cash equivalents, beginning of period	1,889,733	1,303,524
Cash and cash equivalents, end of period	2,635,596	1,730,489
Supplemental disclosures of cash flow information:
Interest Paid, Excluding Capitalized Interest, Operating Activities	124,154	124,575
Income Taxes Paid, Net	14,115	99,554
Transfer to Investments	6,198,117	3,763,195
Capital Expenditures Incurred but Not yet Paid	986	0
Noncash or Part Noncash Acquisition, Value of Assets Acquired	8,303	69,853
Noncash or Part Noncash Acquisition, Value of Liabilities Assumed	$ (11,864)	$ (38,412)