Stockholders' Equity and Statutory Accounting Practices (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Stockholders' Equity and Statutory Accounting Practices [Abstract]
Increase in statutory capital and surplus due to prescribed practice	$ 91	$ 91
Statutory amount available for dividend payment before consideration of statutory dividends paid in the preceding twelve months	1,070
Dividends paid in the preceding twelve months	$ 975
Capital required for capital adequacy to risk weighted assets	2.66	2.91