Retirement Benefits Categorization of Plan Assets (Details 7) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	$ 37,824	$ 35,967
Cash & cash equivalents
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	2,387	1,358
U.S. Equity Securities [Member]
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	3,087	2,981
International equities
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	3,108	3,356
U.S. Treasuries
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	2,836	2,295
U.S. Government Agency
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	180	258
Non-U.S. Government
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	277	332
Corporate debt
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	5,531	6,259
Asset backed
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	987	1,080
High yield debt
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	50	72
Bank loans
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	21	59
Other
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	92	59
Notes Payable, Other Payables [Member]
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	(73)	(232)
Level 1
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	6,412	6,530
Level 1 | Cash & cash equivalents
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	119	120
Level 1 | U.S. Equity Securities [Member]
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	3,085	2,981
Level 1 | International equities
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	3,105	3,354
Level 1 | U.S. Treasuries
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	21	22
Level 1 | Corporate debt
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	30	31
Level 1 | High yield debt
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	19	24
Level 1 | Other
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	33	(2)
Level 2
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	12,139	11,575
Level 2 | Cash & cash equivalents
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	2,268	1,238
Level 2 | U.S. Equity Securities [Member]
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	2	0
Level 2 | U.S. Treasuries
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	2,815	2,273
Level 2 | U.S. Government Agency
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	180	258
Level 2 | Non-U.S. Government
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	277	332
Level 2 | Corporate debt
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	5,501	6,228
Level 2 | Asset backed
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	987	1,080
Level 2 | High yield debt
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	31	48
Level 2 | Bank loans
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	21	59
Level 2 | Other
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	57	59
Level 3
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	5	4
Level 3 | International equities
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	3	2
Level 3 | Other
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	2	2
Fair Value Measured at Net Asset Value Per Share | U.S. Equity Securities [Member]
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	1,652	1,567
Fair Value Measured at Net Asset Value Per Share | International equities
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	6,849	7,193
Fair Value Measured at Net Asset Value Per Share | Fixed Income Funds
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	1,461	1,959
Fair Value Measured at Net Asset Value Per Share | Hedge Funds
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	63	65
Fair Value Measured at Net Asset Value Per Share | OpportunisticFunds
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	3,039	2,499
Fair Value Measured at Net Asset Value Per Share | Private Equity Funds [Member]
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	3,535	2,627
Fair Value Measured at Net Asset Value Per Share | Real Estate Funds [Member]
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Fair value of plan assets	2,742	2,180
Pension and Other Post-retirement benefit plans [Member]
Plan Assets by Fair Value Measurement Input (Table Amounts) [Abstract]
Derivative Asset	78	29
Derivative Liability	(38)	(27)
Derivative, Notional Amount	$ 3,700	$ 2,300