Investments (Other Invested Assets) (Details) - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018
Other Invested Assets
Other invested assets	[1]	$ 15,606	$ 14,526
LPs/LLCs
Other Invested Assets
Other invested assets		11,157	9,841
Real estate held through direct ownership
Other Invested Assets
Other invested assets		2,388	2,466
Derivative Instruments
Other Invested Assets
Other invested assets		877	1,155
Other
Other Invested Assets
Other invested assets		1,184	1,064
Mortgage Debt | Real estate-related
Other Invested Assets
Other invested assets		537	776
Equity method | LPs/LLCs
Other Invested Assets
Other invested assets		6,944	5,726
Equity method | Private equity | LPs/LLCs
Other Invested Assets
Other invested assets		3,625	3,182
Equity method | Hedge funds | LPs/LLCs
Other Invested Assets
Other invested assets		1,947	1,337
Equity method | Real estate-related | LPs/LLCs
Other Invested Assets
Other invested assets		1,372	1,207
Fair Value
Other Invested Assets
Other invested assets		36	40
Fair Value | LPs/LLCs
Other Invested Assets
Other invested assets		4,213	4,115
Fair Value | Private equity | LPs/LLCs
Other Invested Assets
Other invested assets		1,705	1,684
Fair Value | Hedge funds | LPs/LLCs
Other Invested Assets
Other invested assets		2,172	2,135
Fair Value | Real estate-related | LPs/LLCs
Other Invested Assets
Other invested assets		$ 336	$ 296

[1] See Note 4 for details of balances associated with variable interest entities.