Pension And Postretirement Benefits (Narrative) (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended				9 Months Ended		12 Months Ended
	Oct. 15, 2018	Jun. 30, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Actuarial Gain (Loss)							$ 2,726	$ 259
WarnerMedia [Member]
Defined Benefit Plan Disclosure [Line Items]
Business Acquisition, Effective Date of Acquisition		Jun. 14, 2018
Pension Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Net supplemental retirement pension benefits costs			$ 24			$ 22	$ 65	67
Pension Contribution Date							Dec. 31, 2013
Required contribution to pension plans							$ 420
Value of entity's noncash contribution to it's defined benefit plans			8,803				8,803
Defined Benefit Plan, Net Prior Service Cost (Credit) Arising During Period, before tax				$ 50
Defined Benefit Plan, Actuarial Gain (Loss)			$ 0	1,796		0	1,796	0
Postemployment benefit obligation							$ (1,746)
Discount rate for determining projected benefit obligation			4.30%				4.30%
Pension Benefit [Member] | Other Comprehensive Income (Loss) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Amendments				$ (50)
Pension Benefit [Member] | Service Cost [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate in effect for determining net cost							4.40%
Pension Benefit [Member] | Interest Cost [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate in effect for determining net cost							4.00%
Pension Benefit [Member] | Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Contribution Date	Oct. 15, 2018
Required contribution to pension plans									$ 560
Annualized cash distributions to be received by the trust/pension	$ 80
Postretirement Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Prior Service Cost (Credit) Arising During Period, before tax					$ (752)
Defined Benefit Plan, Actuarial Gain (Loss)			$ 0		930	$ 0	$ 930	$ 259
Postemployment benefit obligation							$ (1,682)
Discount rate for determining projected benefit obligation			4.10%				4.10%
Postretirement Benefit [Member] | Other Comprehensive Income (Loss) [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Amendments					$ 752
Postretirement Benefit [Member] | Service Cost [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate in effect for determining net cost							4.30%
Postretirement Benefit [Member] | Interest Cost [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate in effect for determining net cost							3.70%