Shareholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2021	Sep. 30, 2021	Feb. 03, 2021	Oct. 31, 2018	Oct. 25, 2017
Common Stock Repurchase [Line Items]
Accelerated Share Repurchases, Settlement (Payment) or Receipt		$ 400			$ 500
Treasury Stock Acquired, Average Cost Per Share		$ 194.91	$ 199.90
Accelerated Share Repurchases, Cash or Stock Settlement	449,049	2.1 million	2.5 million
Adjustments To Additional Paid In Capital, Equity Forward Contract	$ 100
Stock Repurchase Program, Remaining Authorized Repurchase Amount				$ 773
October Twenty Six Two Thousand Ten Program [Member]
Common Stock Repurchase [Line Items]
Stock Repurchase Program, Authorized Amount						$ 1,000	$ 4,400