SHAREHOLDERS' EQUITY - Summary of Stock Repurchase Activity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended				9 Months Ended
	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020
Stock Repurchase [Roll Forward]
Number of shares repurchased (in shares)	33,438,176				33,438,176
Cost of Shares Repurchased	$ 82	$ 127	$ 109	$ 106
Number of shares repurchased (in shares)					34,187,868
Treasury Stock
Stock Repurchase [Roll Forward]
Number of shares repurchased (in shares)	16,418,950				16,418,950
Cost of Shares Repurchased	$ 1,258				$ 1,258
Average price paid per share (in usd per share)	$ 76.60				$ 76.60
Repurchase of common stock (in shares)					769,935
Cost of Shares Repurchased	$ 82	$ 127	$ 109	$ 106	$ 82
Average price paid per share (in usd per share)					$ 106.60
Number of shares repurchased (in shares)					17,188,885
Cost of Shares Repurchased					$ 1,340
Average price paid per share (in usd per share)					$ 77.95