Shareholders' Equity (Accumulated other comprehensive income) (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2022		Jun. 30, 2021		Jun. 30, 2022	Jun. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	$ (11,370)		$ (16,952)		$ (11,659)	$ (17,133)
OCI before reclassifications	[1]	(244)		76		(126)	53
Amounts reclassified from AOCI	[1]	127		215		298	419
Net current period Other comprehensive income/(loss)	[1]	(117)		291		172	472
Ending Balance	[1]	(11,487)		(16,661)		(11,487)	(16,661)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax		155		235		314	463
Amortization of actuarial losses included in net periodic pension cost, tax		(44)		(57)		(84)	(122)
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net						39
Loss on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Tax						11
Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(81)		(66)		(105)	(30)
OCI before reclassifications		(76)		14		(52)	(22)
Net current period Other comprehensive income/(loss)		(76)		14		(52)	(22)
Ending Balance		(157)		(52)		(157)	(52)
Unrealized Gains and Losses on Certain Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		1		1		1	1
Ending Balance		1		1		1	1
Unrealized Gains and Losses on Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		135		(34)		6	(43)
OCI before reclassifications		(168)		54		(74)	65
Amounts reclassified from AOCI		(5)				30	(2)
Net current period Other comprehensive income/(loss)		(173)		54		(44)	63
Ending Balance		(38)		20		(38)	20
Defined Benefit Pension Plans and Other Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(11,425)		(16,853)		(11,561)	(17,061)
OCI before reclassifications				8			10
Amounts reclassified from AOCI		132	[2]	215	[2]	268	421
Net current period Other comprehensive income/(loss)		132		223		268	431
Ending Balance		$ (11,293)		$ (16,630)		$ (11,293)	$ (16,630)

[1] Net of tax.

[2] Primarily relates to amortization of actuarial losses for the six and three months ended June 30, 2022 of $314 and $155 (net of tax of ($84) and ($44)) and the six and three months ended June 30, 2021 totaling $463 and $235 (net of tax of ($122) and ($57)). These are included in the net periodic pension cost.