Investments - Summary of Maximum Loss Exposure (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Assets	$ 215,549	$ 202,771
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	48,153	40,479
Investment funds | Investments, excluding investments in Related Party
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	1,794	1,265
Related Party | Investment funds
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	8,927	7,989
Debt Securities [Member] | Investments, excluding investments in Related Party
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	27,307	23,027
Debt Securities [Member] | Related Party
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	10,010	8,126
Equity securities | Related Party
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	115	72
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Assets	44,016	37,318
Variable Interest Entity, Not Primary Beneficiary [Member] | Investment funds | Investments, excluding investments in Related Party
Variable Interest Entity [Line Items]
Assets	1,159	803
Variable Interest Entity, Not Primary Beneficiary [Member] | Related Party | Investment funds
Variable Interest Entity [Line Items]
Assets	6,324	5,284
Variable Interest Entity, Not Primary Beneficiary [Member] | Debt Securities [Member] | Investments, excluding investments in Related Party
Variable Interest Entity [Line Items]
Assets	27,808	23,325
Variable Interest Entity, Not Primary Beneficiary [Member] | Debt Securities [Member] | Related Party
Variable Interest Entity [Line Items]
Assets	8,610	7,834
Variable Interest Entity, Not Primary Beneficiary [Member] | Equity securities | Related Party
Variable Interest Entity [Line Items]
Assets	$ 115	$ 72