Shareholders' Equity (Tables)

12 Months Ended

Dec. 31, 2020

Equity [Abstract]

Summary of Shares Outstanding

	Common Stock	Treasury Stock	Shares Outstanding
January 1, 2018	581,146,136	(329,971,737)	251,174,399
Purchases	—	(15,877,364)	(15,877,364)
Issuances	—	564,399	564,399
December 31, 2018	581,146,136	(345,284,702)	235,861,434
Purchases	—	(2,722,800)	(2,722,800)
Issuances	—	2,541,836	2,541,836
December 31, 2019	581,146,136	(345,465,666)	235,680,470
Issuances	—	1,005,795	1,005,795
December 31, 2020	581,146,136	(344,459,871)	236,686,265