Nature of Operations, Basis of Presentation and Summary of Significant Accounting Policies (Summary of Restated Consolidated Statements of Stockholders Equity) (Details) - USD ($) $ in Millions	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Balance	$ 2,668	$ 9,654	$ 15,184	$ 20,754	$ 21,165	$ 21,742	$ 19,587	$ 22,699	$ 20,754	$ 22,699	$ 20,754	$ 22,699	$ 20,754	$ 22,699
Net income (loss)	21	(2,583)	228	92	708	316	645	219	319	864	(2,264)	1,180	(2,241)	1,887	$ 499
Total other comprehensive income (loss), net of tax	960	(4,291)	(5,589)	(5,189)	(408)	(630)	1,718	(3,170)					(14,109)	(2,490)	3,258
Balance	4,569	2,668	9,654	15,184	20,754	21,165	21,742	19,587	9,654	21,742	2,668	21,165	4,569	20,754	22,699
Preferred Stock [Member]
Balance	986												986
Preferred Stock [Member] | Series C Preferred Stock [Member]
Issuance of preferred stock													493
Preferred Stock [Member] | Series D Preferred Stock [Member]
Issuance of preferred stock													493
Common Stock [Member]
Balance	4,534	4,546	4,586	4,735	4,956	5,021	5,057	5,082	4,735	5,082	4,735	5,082	4,735	5,082	5,162
Stock compensation/issued for benefit plans		15	9	6		16	23	25					40	85	48
Retirement of common stock/cancellation of shares		(27)	(49)	(155)		(81)	(59)	(50)					(231)	(432)	(128)
Balance	4,544	4,534	4,546	4,586	4,735	4,956	5,021	5,057	4,546	5,021	4,534	4,956	4,544	4,735	5,082
Retained Earnings [Member]
Balance	6,762	9,445	9,346	9,578	9,360	9,242	8,769	8,686	9,578	8,686	9,578	8,686	9,578	8,686	8,854
Net income (loss)		(2,583)	228	92		316	645	219					(2,241)	1,887	499
Retirement of common stock/cancellation of shares		(23)	(51)	(245)		(119)	(91)	(55)					(319)	(673)	(147)
Common stock dividends declared		(77)	(78)	(79)		(79)	(81)	(81)					(311)	(322)	(317)
Balance	6,707	6,762	9,445	9,346	9,578	9,360	9,242	8,769	9,445	9,242	6,762	9,360	6,707	9,578	8,686
Accumulated Other Comprehensive Income (Loss) [Member]
Balance	(8,628)	(4,337)	1,252	6,441	6,849	7,479	5,761	8,931	6,441	8,931	6,441	8,931	6,441	8,931	5,673
Total other comprehensive income (loss), net of tax		(4,291)	(5,589)	(5,189)		(630)	1,718	(3,170)					(14,109)	(2,490)	3,258
Balance	(7,668)	(8,628)	(4,337)	1,252	6,441	6,849	7,479	5,761	(4,337)	7,479	(8,628)	6,849	(7,668)	6,441	8,931
Cumulative Effect, Period of Adoption, Adjustment [Member] | Retained Earnings [Member]
Balance															(203)
As Previously Reported [Member]
Balance	2,217	9,188	14,712	20,272	21,170	21,745	19,593		20,272		20,272		20,272
Net income (loss)	5	(2,574)	238	104	220	318	642	225	341	867	(2,233)	1,185	(2,227)	1,405
Total other comprehensive income (loss), net of tax	960	(4,285)	(5,593)	(5,191)	(408)	(630)	1,718	(3,170)					(14,109)	(2,490)
Balance	4,101	2,217	9,188	14,712	20,272	21,170	21,745	19,593	9,188	21,745	2,217	21,170	4,101	20,272
As Previously Reported [Member] | Preferred Stock [Member]
Balance	986												986
As Previously Reported [Member] | Preferred Stock [Member] | Series C Preferred Stock [Member]
Issuance of preferred stock													493
As Previously Reported [Member] | Preferred Stock [Member] | Series D Preferred Stock [Member]
Issuance of preferred stock													493
As Previously Reported [Member] | Common Stock [Member]
Balance	4,534	4,546	4,586	4,735	4,956	5,021	5,057	5,082	4,735	5,082	4,735	5,082	4,735	5,082
Stock compensation/issued for benefit plans		15	9	6		16	23	25					40	85
Retirement of common stock/cancellation of shares		(27)	(49)	(155)		(81)	(59)	(50)					(231)	(432)
Balance	4,544	4,534	4,546	4,586	4,735	4,956	5,021	5,057	4,546	5,021	4,534	4,956	4,544	4,735	5,082
As Previously Reported [Member] | Retained Earnings [Member]
Balance	6,311	8,985	8,876	9,096	9,365	9,245	8,775	8,686	9,096	8,686	9,096	8,686	9,096	8,686
Net income (loss)		(2,574)	238	104		318	642	225					(2,227)	1,405
Retirement of common stock/cancellation of shares		(23)	(51)	(245)		(119)	(91)	(55)					(319)	(673)
Common stock dividends declared		(77)	(78)	(79)		(79)	(81)	(81)					(311)	(322)
Balance	6,239	6,311	8,985	8,876	9,096	9,365	9,245	8,775	8,985	9,245	6,311	9,365	6,239	9,096	8,686
As Previously Reported [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Balance	(8,628)	(4,343)	1,250	6,441	6,849	7,479	5,761	8,931	6,441	8,931	6,441	8,931	6,441	8,931
Total other comprehensive income (loss), net of tax		(4,285)	(5,593)	(5,191)		(630)	1,718	(3,170)					(14,109)	(2,490)
Balance	(7,668)	(8,628)	(4,343)	1,250	6,441	6,849	7,479	5,761	(4,343)	7,479	(8,628)	6,849	(7,668)	6,441	$ 8,931
Restatement Impacts [Member]
Balance	451	466	472	482	(5)	(3)	(6)		482		482		482
Net income (loss)	16	(9)	(10)	(12)	488	(2)	3	(6)	(22)	(3)	(31)	(5)	(14)	482
Total other comprehensive income (loss), net of tax		(6)	4	2
Balance	468	451	466	472	482	(5)	(3)	(6)	466	(3)	451	(5)	468	482
Restatement Impacts [Member] | Retained Earnings [Member]
Balance	451	460	470	482	(5)	(3)	(6)		482		482		482
Net income (loss)		(9)	(10)	(12)		(2)	3	(6)					(14)	482
Balance	$ 468	451	460	470	$ 482	$ (5)	$ (3)	$ (6)	460	$ (3)	$ 451	$ (5)	$ 468	$ 482
Restatement Impacts [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Balance		6	2
Total other comprehensive income (loss), net of tax		$ (6)	4	2
Balance			$ 6	$ 2					$ 6