(Fair Values Pension Plan Assets By Asset Class) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	$ 10,165	$ 8,735	$ 11,368
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	2,900	2,120
Significant Observable Inputs (Level 2) [Member] | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	5,074	4,156
Significant Unobservable Inputs (Level 3) [Member] | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	(5)	111	29
Equity Securities, US [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	1,613	1,200
Equity Securities, US [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	965	685
Equity Securities, US [Member] | Significant Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	648	515
Equity Securities, US [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	0	0
Equity Securities, Non-US [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	2,181	1,583
Equity Securities, Non-US [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	1,599	1,141
Equity Securities, Non-US [Member] | Significant Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	582	442
Equity Securities, Non-US [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	0	0
Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	1,845	1,493
Corporate Bonds [Member] | Significant Observable Inputs (Level 2) [Member] | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	1,845	1,493
Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	2,659	2,262
Government Securities [Member] | Significant Observable Inputs (Level 2) [Member] | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	2,659	2,262
Mortgage Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	1
Mortgage Backed Securities [Member] | Significant Observable Inputs (Level 2) [Member] | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	1
Mortgage Backed Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	0	0	1
Other Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	(647)	(543)
Other Fixed Income [Member] | Significant Observable Inputs (Level 2) [Member] | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	(661)	(556)
Other Fixed Income [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	14	13	12
Derivatives [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	(19)	98
Derivatives [Member] | Significant Unobservable Inputs (Level 3) [Member] | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	(19)	98	$ 16
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	336	294
Cash and Cash Equivalents [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	336	294
Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Alternative investment	902	886
Private Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Alternative investment	522	518
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Alternative investment	$ 772	$ 944