Employee Benefits (Tables)

12 Months Ended

Dec. 31, 2019

Retirement Benefits [Abstract]

Change In Benefit Obligations, Change In Plan Assets, Funded Status, Amounts Recognized on Balance Sheet, and Amounts Recognized In Accumulated Other Comprehensive Income (Pretax)

The following tables summarize benefit costs, as well as the benefit obligations, plan assets, funded status and rate assumptions associated with pension and postretirement health care and life insurance benefit plans.

Obligations and Funded Status

							(dollars in millions)
	Pension						Health Care and Life
At December 31,	2019			2018			2019			2018
Change in Benefit Obligations
Beginning of year	$	19,567		$	21,531		$	16,364		$	19,460
Service cost	247			284			96			127
Interest cost	695			690			629			615
Plan amendments	—			230			(22		)	(8		)
Actuarial (gain) loss, net	2,860			(1,418		)	(414		)	(2,729		)
Benefits paid	(1,248		)	(1,475		)	(984		)	(1,101		)
Curtailment and termination benefits	—			181			—			—
Settlements paid	(873		)	(456		)	—			—
End of year	21,248			19,567			15,669			16,364
Change in Plan Assets
Beginning of year	17,816			19,175			1,175			1,119
Actual return on plan assets	3,385			(494		)	103			(26		)
Company contributions	371			1,066			449			1,183
Benefits paid	(1,248		)	(1,475		)	(984		)	(1,101		)
Settlements paid	(873		)	(456		)	—			—
End of year	19,451			17,816			743			1,175
Funded Status
End of year	$	(1,797	)	$	(1,751	)	$	(14,926	)	$	(15,189	)

							(dollars in millions)
	Pension						Health Care and Life
At December 31,	2019			2018			2019			2018
Amounts recognized on the balance sheet
Noncurrent assets	$	5		$	3		$	—		$	—
Current liabilities	(67		)	(71		)	(603		)	(292		)
Noncurrent liabilities	(1,735		)	(1,683		)	(14,323		)	(14,897		)
Total	$	(1,797	)	$	(1,751	)	$	(14,926	)	$	(15,189	)
Amounts recognized in Accumulated Other Comprehensive Income (Pre-tax)
Prior service cost (benefit)	$	524		$	585		$	(3,749	)	$	(4,698	)
Total	$	524		$	585		$	(3,749	)	$	(4,698	)

Information for Pension Plans with Accumulated Benefit Obligation in Excess of Plan Assets

Information for pension plans with an accumulated benefit obligation in excess of plan assets follows:

	(dollars in millions)
At December 31,	2019		2018
Projected benefit obligation	$	21,190	$	19,510
Accumulated benefit obligation	21,134		19,461
Fair value of plan assets	19,388		17,757

Benefit or (Income) Cost Related to Pension and Postretirement Health Care and Life Insurance

The following table summarizes the components of net periodic benefit cost (income) related to our pension and postretirement health care and life insurance plans:

													(dollars in millions)
	Pension									Health Care and Life
Years Ended December 31,	2019			2018			2017			2019			2018			2017
Service cost - Cost of services	$	202		$	230		$	215		$	78		$	104		$	116
Service cost - Selling, general and administrative expense	45			54			65			18			23			33
Service cost	247			284			280			96			127			149
Amortization of prior service cost (credit)	61			48			39			(971		)	(976		)	(949		)
Expected return on plan assets	(1,130		)	(1,293		)	(1,262		)	(37		)	(44		)	(53		)
Interest cost	695			690			683			629			615			659
Remeasurement loss (gain), net	606			369			337			(480		)	(2,658		)	546
Curtailment and termination benefits	—			181			11			—			—			—
Other components	232			(5		)	(192		)	(859		)	(3,063		)	203
Total	$	479		$	279		$	88		$	(763	)	$	(2,936	)	$	352

Other Pretax Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive (Income) Loss

Other pre-tax changes in plan assets and benefit obligations recognized in other comprehensive (income) loss are as follows:

										(dollars in millions)
	Pension									Health Care and Life
At December 31,	2019			2018			2017			2019			2018			2017
Prior service cost (benefit)	$	—		$	230		$	—		$	(22	)	$	(8	)	$	(544	)
Reversal of amortization items
Prior service cost (benefit)	(61		)	(48		)	(39		)	971			976			949
Total recognized in other comprehensive loss (income) (pre-tax)	$	(61	)	$	182		$	(39	)	$	949		$	968		$	405

Weighted Average Assumptions Used in Determining Benefit Obligations and Net Periodic Cost

The weighted-average assumptions used in determining benefit obligations follow:

	Pension				Health Care and Life
At December 31,	2019		2018		2019		2018
Discount Rate	3.30	%	4.40	%	3.20	%	4.30	%
Rate of compensation increases	3.00		3.00		N/A		N/A

The weighted-average assumptions used in determining net periodic cost follow:

	Pension						Health Care and Life
At December 31,	2019		2018		2017		2019		2018		2017
Discount rate in effect for determining service cost	4.60	%	4.10	%	4.70	%	4.60	%	3.90	%	4.60	%
Discount rate in effect for determining interest cost	3.80		3.40		3.40		4.00		3.20		3.50
Expected return on plan assets	6.80		7.00		7.70		4.30		4.80		4.50
Rate of compensation increases	3.00		3.00		3.00		N/A		N/A		N/A

Health Care Cost Trend Rates

The assumed health care cost trend rates are as follows:

	Health Care and Life
At December 31,	2019		2018		2017
Healthcare cost trend rate assumed for next year	6.10	%	6.30	%	7.00	%
Rate to which cost trend rate gradually declines	4.50		4.50		4.50
Year the rate reaches the level it is assumed to remain thereafter	2027		2027		2026

Effects of One Percentage Point Change in Assumed Health Care Cost Trend Rates

A one-percentage point change in the assumed health care cost trend rate would have the following effects:

	(dollars in millions)
One-Percentage Point	Increase		Decrease
Effect on 2019 service and interest cost	$	20	$	(21	)
Effect on postretirement benefit obligation as of December 31, 2019	626		(696		)

Fair Values for Plans by Asset Category

The fair values for the pension plans by asset category at December 31, 2019 are as follows:

	(dollars in millions)
Asset Category	Total		Level 1		Level 2		Level 3
Cash and cash equivalents	$	1,529	$	1,507	$	22	$	—
Equity securities	2,988		2,850		135		3
Fixed income securities
U.S. Treasuries and agencies	1,986		1,768		218		—
Corporate bonds	3,818		524		3,149		145
International bonds	1,355		25		1,304		26
Other	768		—		768		—
Real estate	810		—		—		810
Other
Private equity	737		—		—		737
Hedge funds	293		—		164		129
Total investments at fair value	14,284		6,674		5,760		1,850
Investments measured at NAV	5,167
Total	$	19,451	$	6,674	$	5,760	$	1,850

The fair values for the pension plans by asset category at December 31, 2018 are as follows:

	(dollars in millions)
Asset Category	Total		Level 1		Level 2		Level 3
Cash and cash equivalents	$	1,701	$	1,694	$	7	$	—
Equity securities	2,253		2,220		20		13
Fixed income securities
U.S. Treasuries and agencies	1,684		1,557		127		—
Corporate bonds	3,645		124		3,244		277
International bonds	1,113		19		1,076		18
Other	—		—		—		—
Real estate	727		—		—		727
Other
Private equity	664		—		—		664
Hedge funds	459		—		373		86
Total investments at fair value	12,246		5,614		4,847		1,785
Investments measured at NAV	5,570
Total	$	17,816	$	5,614	$	4,847	$	1,785

Health Care and Life Plans

The fair values for the other postretirement benefit plans by asset category at December 31, 2019 are as follows:

	(dollars in millions)
Asset Category	Total		Level 1		Level 2		Level 3
Cash and cash equivalents	$	220	$	167	$	53	$	—
Equity securities	225		225		—		—
Fixed income securities
U.S. Treasuries and agencies	28		28		—		—
Corporate bonds	76		76		—		—
International bonds	18		18		—		—
Total investments at fair value	567		514		53		—
Investments measured at NAV	176
Total	$	743	$	514	$	53	$	—

The fair values for the other postretirement benefit plans by asset category at December 31, 2018 are as follows:

	(dollars in millions)
Asset Category	Total		Level 1		Level 2		Level 3
Cash and cash equivalents	$	471	$	431	$	40	$	—
Equity securities	239		239		—		—
Fixed income securities
U.S. Treasuries and agencies	24		24		—		—
Corporate bonds	96		96		—		—
International bonds	18		18		—		—
Total investments at fair value	848		808		40		—
Investments measured at NAV	327
Total	$	1,175	$	808	$	40	$	—

Reconciliation of Beginning and Ending Balance of Plan Assets Measured at Fair Value

The following is a reconciliation of the beginning and ending balance of pension plan assets that are measured at fair value using significant unobservable inputs:

	(dollars in millions)
	Equity Securities			Corporate Bonds			International Bonds			Real Estate			Private Equity		Hedge Funds			Total
Balance at January 1, 2018	$	1		$	104		$	20		$	627		$	580	$	185		$	1,517
Actual gain (loss) on plan assets	1			(7		)	3			134			25		—			156
Purchases (sales)	11			177			(5		)	(34		)	59		62			270
Transfers out	—			3			—			—			—		(161		)	(158		)
Balance at December 31, 2018	13			277			18			727			664		86			1,785
Actual gain (loss) on plan assets	1			(1		)	(1		)	30			32		—			61
Purchases (sales)	(11		)	18			9			53			41		116			226
Transfers out	—			(149		)	—			—			—		(73		)	(222		)
Balance at December 31, 2019	$	3		$	145		$	26		$	810		$	737	$	129		$	1,850

Expected Benefit Payments to Retirees

The benefit payments to retirees are expected to be paid as follows:

			(dollars in millions)
Year	Pension Benefits		Health Care and Life
2020	$	2,227	$	961
2021	1,680		947
2022	1,620		930
2023	1,577		968
2024	1,072		951
2025 to 2029	5,248		4,569

Schedule of Recorded Severance Liability

The following table provides an analysis of our severance liability:

								(dollars in millions)
Year	Beginning of Year		Charged to Expense		Payments			Other			End of Year
2017	$	656	$	581	$	(564	)	$	(46	)	$	627
2018	627		2,093		(560		)	(4		)	2,156
2019	2,156		260		(1,847		)	(4		)	565