Retirement Plans (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) plan	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2021 USD ($) employees
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount				$ 520
Change in basis point for assumptions for next year	25.00%
Defined contribution plan, cost recognized	$ 172	$ 154	$ 172
Number of nonqualified pension plans | plan	2
Defined Contribution Plan, Number of Employees | employees				900
Divestitures	$ (287)
Defined Benefit Plan, Plan Assets, Divestiture	(255)
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Benefits paid	(573)	(556)
Expected future benefit payment, next twelve months	589
Defined benefit plan, plan assets, amount	$ 12,075	$ 12,018	$ 10,165
Actuarial assumptions used to determine benefit obligations, Discount rate	2.90%	2.60%	3.40%
Total recognized in other comprehensive income	$ (1,123)
Amount recognized in net periodic benefit cost (credit) and other comprehensive (income) loss, before tax	(1,000)	$ (500)	$ (172)
Accumulated benefit obligation for defined benefit plans	11,800	13,000
Settlement loss	0	0	0
Settlements	$ 0	0
Expected long term return on assets for next year	6.00%
Expected discount rate for next year	2.90%
Rate of compensation increase	2.25%
Expected benefit cost estimate for next fiscal year	$ (114)
Defined benefit expense	(112)	32	93
Divestitures	(287)	0
Defined Benefit Plan, Plan Assets, Divestiture	(255)	0
U.S. Plans | Printing Papers [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit expense	(3)
Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Benefits paid	(5)	(7)
Defined benefit plan, plan assets, amount	$ 19	$ 190	$ 183
Actuarial assumptions used to determine benefit obligations, Discount rate	2.59%	2.32%	2.70%
Total recognized in other comprehensive income	$ (78)
Amount recognized in net periodic benefit cost (credit) and other comprehensive (income) loss, before tax	(73)	$ 13	$ 24
Accumulated benefit obligation for defined benefit plans	56	246
Settlement loss	0	1	2
Settlements	0	(5)
Defined benefit expense	4	5	6
Divestitures	(187)	(1)
Defined Benefit Plan, Plan Assets, Divestiture	(175)	0
Supplemental Employee Retirement Plan, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Benefits paid	(21)	(31)	$ (26)
Expected future benefit payment, next twelve months	21
Other fixed income
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	(1,482)	(1,585)
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	$ 266	$ 210