Retirement Plans (Reconciliation of Benefit Obligations And Plan or Trust Assets And Resulting Funded Status Of Defined Benefit Retirement Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in Benefit Obligation
Settlement/curtailment/other		$ 553
Change in Plan/Trust Assets
Settlement/curtailment/other	$ (551)
Pension Benefits
Change in Benefit Obligation
Benefit obligation at beginning of year	(19,692)	(18,107)
Service cost	(119)	(115)	$ (111)
Interest cost	(360)	(491)	(600)
Amendments	3	37
Actuarial gain (loss)	955	(1,780)
Settlement/curtailment/other		(65)
Benefits paid	881	829
Benefit obligation at end of year	(17,779)	(19,692)	(18,107)
Change in Plan/Trust Assets
Fair value of assets at beginning of year	14,751	13,177
Actual return on plan assets	1,692	1,843
Employer contributions	135	480
Settlement/curtailment/other		58
Benefits paid	(860)	(807)
Fair value of assets at end of year	15,167	14,751	13,177
Funded status at end of year	(2,612)	(4,941)
Other  Post-retirement Benefits
Change in Benefit Obligation
Benefit obligation at beginning of year	(1,062)	(1,027)
Service cost	(10)	(10)	(8)
Interest cost	(19)	(27)	(35)
Amendments	4	2
Actuarial gain (loss)	187	(60)
Settlement/curtailment/other	0	(4)
Benefits paid	60	64
Benefit obligation at end of year	(840)	(1,062)	(1,027)
Change in Plan/Trust Assets
Fair value of assets at beginning of year	705	644
Actual return on plan assets	114	102
Employer contributions	0	0
Settlement/curtailment/other	0	0
Benefits paid	(42)	(41)
Fair value of assets at end of year	777	705	$ 644
Funded status at end of year	$ (63)	$ (357)