Pension and Postretirement Benefit Plans - Additional Information (Details) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2017 plan
Defined Benefit Plan Disclosure [Line Items]
Pension settlement charge	$ 2	$ 258		$ 260
Pension Plan [Member] | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Number Of Plans Terminated | plan						1
Pension settlement charge				$ 258
Pension Plan [Member] | UNITED STATES | Terminated Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to the terminated plan		62
Unfunded pension obligation reduction		165
Pension settlement charge		$ 258