Income Taxes (Schedule Of Reconciliation Of U.S. Federal Statutory Tax Rate To Our Effective Income Tax Rate) (Details) - USD ($) $ in Millions		3 Months Ended				12 Months Ended
		Dec. 31, 2020	[2]	Dec. 31, 2019	Sep. 30, 2018	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Income Tax Examination [Line Items]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount						$ (3,039)	$ (474)		$ 2,437
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount						2,603	25		22
Effective Income Tax Rate Reconciliation, CARES Act, Amount	[1]					(1,175)
Effective Income Tax Rate Reconciliation, Tax Settlement, Amount		$ (587)		$ 371	$ 412		(371)	[2]	(412)	[2]
Effective Income Tax Rate Reconciliation, Tax Credit, Amount						(284)	(382)		(207)
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount						234	66		91
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount						(168)	(45)		75
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Payment Arrangement, Amount	[3]					82	180		181
Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act, Transition Tax on Accumulated Foreign Earnings, Amount	[4]					31	229		549
Effective Income Tax Rate Reconciliation, Deduction, Dividends, Amount						(13)	(53)		(48)
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount						7	20		27
Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act, Amount	[5]								(111)
Total income tax (benefit)/expense						$ (2,535)	$ (1,623)		$ 1,144
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent						21.00%	21.00%		21.00%		35.00%
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent						(18.00%)	(1.10%)		0.20%
Effective Income Tax Rate Reconciliation, CARES Act, Percent	[1]					8.10%
Effective Income Tax Rate Reconciliation, Tax Settlement, Percent	[2]					4.10%	16.40%		(3.60%)
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Percent						2.00%	16.90%		(1.80%)
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent						(1.70%)	(3.00%)		1.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent						1.20%	2.00%		0.60%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Payment Arrangement, Percent	[3]					0.60%	8.00%		(1.60%)
Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act, Transition Tax on Accumulated Foreign Earnings, Percent	[4]					0.20%	10.10%		(4.70%)
Effective Income Tax Rate Reconciliation, Deduction, Dividend, Percent						(0.10%)	(2.40%)		0.40%
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent						(0.10%)	(0.90%)		0.20%
Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act, Percent	[5]								(0.010)
Effective income tax rate						17.50%	71.80%		9.90%

[1] The following is a reconciliation of the U.S. federal statutory tax to actual income tax expense: Years ended December 31,202020192018AmountRateAmountRateAmountRateU.S. federal statutory tax($3,039)21.0 %($474)21.0 %$2,437 21.0 %Valuation allowance2,603 (18.0)25 (1.1)22 0.2  Impact of CARES Act (1) (1,175)8.1  Audit settlements(2) (587)4.1 (371)16.4 (412)(3.6)Research and development credits(284)2.0 (382)16.9 (207)(1.8)Other provision adjustments234 (1.7)66 (3.0)91 1.0 State income tax provision, net of effects on U.S. federal tax(168)1.2 (45)2.0 75 0.6  Excess tax benefits(3) (82)0.6 (180)8.0 (181)(1.6) Foreign derived intangible income(4) (31)0.2 (229)10.1 (549)(4.7)Tax deductible dividends(13)0.1 (53)2.4 (48)(0.4)Tax on non-US activities7 (0.1)20 (0.9)27 0.2  Impact of Tax Cuts and Jobs Act(5) (111)(1.0)Income tax (benefit)/expense($2,535)17.5 %($1,623)71.8 %$1,144 9.9 %
(1)    On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security (CARES) Act was enacted, which includes a five year net operating loss (NOL) carryback provision which enabled us to benefit from certain losses and re-measure certain deferred tax assets and liabilities at the former federal tax rate of 35%. In 2020, we recorded tax benefits of $1,175 related to the NOL carryback provision. (2)    In the fourth quarter of 2020, we recorded a tax benefit of $587 related to the settlement of the 2015-2017 federal tax audit. In the fourth quarter of 2019, we recorded a tax benefit of $371 related to the settlement of state tax audits spanning 15 tax years. In the third quarter of 2018, we recorded a tax benefit of $412 related to the settlement of the 2013-2014 federal tax audit. (3)    In 2020, 2019 and 2018, we recorded excess tax benefits related to employee share-based payments of $82, $180 and $181, respectively. (4)    In 2020, 2019 and 2018, we recorded tax benefits related to foreign derived intangible income of $31, $229 and $549, respectively which effectively apply a lower U.S. tax rate to intangible income derived from serving non-U.S. markets. (5)    During the fourth quarter of 2018 and in accordance with U.S. Securities and Exchange Commission Staff Accounting Bulletin No. 118, the Company completed its accounting for the provisional amounts recognized at December 31, 2017 and recorded an incremental benefit related to refinements to these provisional amounts which was not significant.

[2] In the fourth quarter of 2020, we recorded a tax benefit of $587 related to the settlement of the 2015-2017 federal tax audit. In the fourth quarter of 2019, we recorded a tax benefit of $371 related to the settlement of state tax audits spanning 15 tax years. In the third quarter of 2018, we recorded a tax benefit of $412 related to the settlement of the 2013-2014 federal tax audit.

[3] In 2020, 2019 and 2018, we recorded excess tax benefits related to employee share-based payments of $82, $180 and $181, respectively.

[4] In 2020, 2019 and 2018, we recorded tax benefits related to foreign derived intangible income of $31, $229 and $549, respectively which effectively apply a lower U.S. tax rate to intangible income derived from serving non-U.S. markets.

[5] During the fourth quarter of 2018 and in accordance with U.S. Securities and Exchange Commission Staff Accounting Bulletin No. 118, the Company completed its accounting for the provisional amounts recognized at December 31, 2017 and recorded an incremental benefit related to refinements to these provisional amounts which was not significant.