Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Schedule of components of income tax benefit (provision)

Components of income tax (provision) benefit
	Year Ended December 31,
(in millions)	2021		2020		2019
Current tax (provision) benefit:
Federal	$	—	$	94	$	94
State and local	(1)		3		(39)
International	(3)		(5)		(13)
Deferred tax (provision) benefit:
Federal	(130)		2,766		(1,343)
State and local	16		344		(130)
Income tax (provision) benefit	$	(118)	$	3,202	$	(1,431)

Schedule of effective income tax rate reconciliation

The following table presents the principal reasons for the difference between the effective tax rate and the U.S. federal statutory income tax rate:

Reconciliation of statutory federal income tax rate to the effective income tax rate
	Year Ended December 31,
	2021		2020		2019
U.S. federal statutory income tax rate	21.0	%	21.0	%	21.0	%
State taxes, net of federal benefit	(4.4)		1.9		2.3
Permanent differences	4.9		(0.6)		(0.3)
Valuation allowance	9.1		(2.6)		0.7
Other	(0.8)		0.8		(0.6)
Effective income tax rate	29.8	%	20.5	%	23.1	%

Schedule of significant components of deferred income tax assets and liabilities

Significant components of deferred income tax assets and liabilities
	December 31,
(in millions)	2021		2020
Deferred tax assets:
Net operating loss carryforwards	$	1,301	$	1,495
Capital loss carryforward	480		483
Pension, postretirement and other benefits	2,089		2,956
Investments	314		—
Deferred revenue	2,288		1,929
Lease liabilities	2,452		2,185
Other	494		479
Valuation allowance	(833)		(460)
Total deferred tax assets	$	8,585	$	9,067
Deferred tax liabilities:
Depreciation	$	4,463	$	4,507
Operating lease assets	1,676		1,324
Intangible assets	1,097		1,076
Other	55		172
Total deferred tax liabilities	$	7,291	$	7,079
Net deferred tax assets	$	1,294	$	1,988

Schedule of valuation allowance on deferred income tax assets

The following table presents the balance of our valuation allowance on our deferred income tax assets and the associated activity:

Valuation allowance activity
(in millions)	2021		2020
Balance at January 1	$	460	$	58
Tax provision	26		402
Equity investment activity	347		—
Balance at December 31	$	833	$	460