Retirement Plans (Reconciliation of The Change In AOCL For Defined-Benefit Retirement Plans) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amortization of:
Prior service credit		$ (22)	$ (50)	$ (69)
Change in AOCL, pretax		886	61	$ (20)
Pension Benefits
Compensation And Retirement Disclosure Line Items
Net actuarial loss (gain)		1,151	422
Prior service credit (cost)		3	(15)
Amortization of:
Net actuarial (loss) gain from prior years		(326)	(359)
Prior service credit		19	46
Other	[1]	0	(5)
Change in AOCL, pretax		847	89
Other Post-retirement Benefits
Compensation And Retirement Disclosure Line Items
Net actuarial loss (gain)		20	(34)
Prior service credit (cost)		8	0
Amortization of:
Net actuarial (loss) gain from prior years		8	4
Prior service credit		3	4
Other	[1]	0	(2)
Change in AOCL, pretax		$ 39	$ (28)

[1] Includes foreign exchange translation, curtailment and other adjustments.