Fair Value of Assets and Liabilities (Changes in Level 3 Assets and Liabilities) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		$ 77	$ 33	$ 0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	3	33	14
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	0	(1)	(7)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0	0	39
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		14	0	0
Fair Value, Asset Value, End of period		53	77	33
Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		2,186	1,331	1,337
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		28	48	(33)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	1,193	1,050	509
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	(182)	(81)	(106)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	(229)	(194)	(273)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		57	43	10
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		4	1	107
Fair Value, Asset Value, End of period		3,029	2,186	1,331
Debt Security, Government, Non-US [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		720	533	599
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		1	162	(80)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	0	10	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		704	0	0
Fair Value, Asset Value, End of period		17	720	533
Structured Finance [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		208	103	235
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		(7)	4	(3)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	149	85	94
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	(5)	(1)	(7)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	(59)	(63)	(62)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		38	86	78
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		70	6	234
Fair Value, Asset Value, End of period		254	208	103
US Government Agencies Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		25	28	64
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		1	1	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	(3)	(4)	(5)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0	0	10
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0	0	41
Fair Value, Asset Value, End of period		23	25	28
Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		121	110	122
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	60	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0	0	0
Fair Value, Asset Value, End of period		114	121	110
Longevity Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		0	48	39
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		0	(2)	(2)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	0	(58)	(2)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0	0	0
Fair Value, Asset Value, End of period		0	0	48
Short-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset Value, Beginning of period		2	2	3
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)		0	(1)	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	[1]	17	30	3
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	[1]	0	(1)	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	[1]	(3)	(1)	(1)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		1	27	3
Fair Value, Asset Value, End of period		15	2	2
Interest Sensitive Contract Liabilities Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales	[1]	0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3		0	0	0
Fair Value, Liability Value, Beginning of period		(930)	(945)	(1,014)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)		0	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	[1]	(32)	(17)	(19)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	[1]	77	84	76
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3		0	0	0
Fair Value, Liability Value, End of period		(907)	(930)	(945)
Investment Income [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Investment Income [Member] | Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		2	1	(1)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	2	(1)
Investment Income [Member] | Debt Security, Government, Non-US [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	15	14
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	15	14
Investment Income [Member] | Structured Finance [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Investment Income [Member] | US Government Agencies Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Investment Income [Member] | Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(4)	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		(4)	0	0
Investment Income [Member] | Longevity Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Investment Income [Member] | Short-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Investment Income [Member] | Interest Sensitive Contract Liabilities Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Investment Related Gains Losses [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(13)	12	(13)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		(13)	12	(16)
Investment Related Gains Losses [Member] | Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(22)	(11)	(5)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		(23)	(11)	(6)
Investment Related Gains Losses [Member] | Debt Security, Government, Non-US [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Investment Related Gains Losses [Member] | Structured Finance [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	2
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Investment Related Gains Losses [Member] | US Government Agencies Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Investment Related Gains Losses [Member] | Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		(63)	11	(12)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		(63)	11	(12)
Investment Related Gains Losses [Member] | Longevity Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Investment Related Gains Losses [Member] | Short-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Investment Related Gains Losses [Member] | Interest Sensitive Contract Liabilities Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		(8)	(5)	15
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)		(2)	(3)	(22)
Interest Income [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Interest Income [Member] | Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Interest Income [Member] | Debt Security, Government, Non-US [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Interest Income [Member] | Structured Finance [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Interest Income [Member] | US Government Agencies Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Interest Income [Member] | Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Interest Income [Member] | Longevity Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Interest Income [Member] | Short-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Interest Income [Member] | Interest Sensitive Contract Liabilities Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		30	57	(27)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)		(107)	(140)	(49)
Other Income [Member] | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Other Income [Member] | Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Other Income [Member] | Debt Security, Government, Non-US [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Other Income [Member] | Structured Finance [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Other Income [Member] | US Government Agencies Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Other Income [Member] | Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Other Income [Member] | Longevity Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	12	9
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	9
Other Income [Member] | Short-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	0	0
Other Income [Member] | Interest Sensitive Contract Liabilities Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings		0	0	0
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)		0	$ 0	$ 0
Other Comprehensive Income (Loss) | Equity Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0
Other Comprehensive Income (Loss) | Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		(34)
Other Comprehensive Income (Loss) | Debt Security, Government, Non-US [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		1
Other Comprehensive Income (Loss) | Structured Finance [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		(8)
Other Comprehensive Income (Loss) | US Government Agencies Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		1
Other Comprehensive Income (Loss) | Funds Withheld At Interest Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0
Other Comprehensive Income (Loss) | Longevity Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0
Other Comprehensive Income (Loss) | Short-term Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		0
Other Comprehensive Income (Loss) | Interest Sensitive Contract Liabilities Embedded Derivatives [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward]
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)		$ 0

[1] The amount reported within purchases, sales and settlements is the purchase price (for purchases) and the sales/settlement proceeds (for sales and settlements) based upon the actual date purchased or sold/settled. Items purchased and sold/settled in the same period are excluded from the rollforward. The Company had no issuances during the period.