Employee Benefit Plans - Narrative (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) plan	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Multiemployer plan, contributions by employer	$ 3,000,000	$ 158,000,000	$ 132,000,000
Health care cost trend rate assumed next fiscal year	6.50%
Health care cost trend rate	4.50%
Defined contribution plan, employer matching contribution per dollar	$ 1.00
Defined contribution plan, employer matching contribution	5.00%
Defined contribution plan, employers matching contribution for vesting plan	4.00%
Defined contribution plan, employers matching contribution for vesting, period	3 years
Defined contribution plans, cost	$ 235,000,000	137,000,000
Number of non-qualified defined contribution plans | plan	2
Defined contribution plan, assets and liabilities	$ 276,000,000	233,000,000
Pension plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension assets or obligations, threshold, per plan	20,000,000
Expected amortization of gain (loss), next fiscal year	(32,000,000)
Expected amortization of prior service cost (credit), next fiscal year	1,000,000
Fair values of the plan assets	3,004,000,000	1,866,000,000	2,059,000,000
Employer contributions	23,000,000	51,000,000
Estimated future employer contributions in next fiscal year	21,000,000
Pension plan | Fixed income and cash investment funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair values of the plan assets	1,858,000,000	937,000,000
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected amortization of gain (loss), next fiscal year	3,000,000
Expected amortization of prior service cost (credit), next fiscal year	3,000,000
Fair values of the plan assets	0	0	$ 0
Employer contributions	16,000,000	21,000,000
Estimated future employer contributions in next fiscal year	$ 11,000,000
U.S. | Pension plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of retirement plans | plan	4
Foreign | Pension plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Number of retirement plans | plan	7
Fair value measured at Net Asset Value per share
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair values of the plan assets	$ 2,988,000,000	$ 1,802,000,000
Fair value measured at Net Asset Value per share | Equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Percent of plan assets valued using NAV	20.00%	30.00%
Fair value measured at Net Asset Value per share | Fixed income and cash investment funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Percent of plan assets valued using NAV	62.00%	48.00%
Fair value measured at Net Asset Value per share | Alternative investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Percent of plan assets valued using NAV	18.00%	19.00%
Fair Value, Inputs, Level 1, 2 and 3 | Pension plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair values of the plan assets	$ 14,000,000	$ 64,000,000
Level 3 | Pension plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair values of the plan assets	$ 0	$ 0