Consolidated Statements Of Stockholders' Equity - USD ($) $ in Millions	Cumulative Effect, Period of Adoption, Adjustment [Member] Retained Earnings [Member]	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance as of beginning-of-period at Dec. 31, 2018		$ 5,392	$ 8,551	$ 407
Stock compensation/issued for benefit plans		42
Net income (loss)			886		$ 886
Retirement of common stock/cancellation of shares		(272)	(278)
Common stock dividends declared			(305)
Total other comprehensive income (loss), net of tax				5,266	5,266
Balance as of end-of-period at Dec. 31, 2019	$ (203)	5,162	8,854	5,673	19,689
Stock compensation/issued for benefit plans		48
Net income (loss)			499		499
Retirement of common stock/cancellation of shares		(128)	(147)
Common stock dividends declared			(317)
Total other comprehensive income (loss), net of tax				3,258	3,258
Balance as of end-of-period at Dec. 31, 2020		5,082	8,686	8,931	22,699
Stock compensation/issued for benefit plans		85
Net income (loss)			1,405		1,405
Retirement of common stock/cancellation of shares		(432)	(673)
Common stock dividends declared			(322)
Total other comprehensive income (loss), net of tax				(2,490)	(2,490)
Balance as of end-of-period at Dec. 31, 2021		$ 4,735	$ 9,096	$ 6,441	$ 20,272