Shareholders' Equity - Regulatory Requirements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statutory Accounting Practices [Line Items]
Estimated minimum statutory surplus required by regulators	$ 7,261
Investments on deposit with regulatory bodies	794
Estimated maximum dividend distributions permitted in 2022 without prior regulatory approval	2,939
Insurance and HMO
Statutory Accounting Practices [Line Items]
Combined statutory net income	3,302	$ 3,667	$ 2,842
Combined statutory capital and surplus	14,879	$ 13,238	$ 10,975
Dividends paid	$ 1,600