SHAREHOLDERS' INTEREST - Additional Information (Details) $ / shares in Units, $ in Millions			1 Months Ended	3 Months Ended		12 Months Ended
	Jul. 01, 2016 shares	Jun. 24, 2013 USD ($) $ / shares shares	Jun. 28, 2016 $ / shares	Dec. 31, 2018 USD ($) $ / shares shares	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 shares	Nov. 08, 2015 USD ($)
Class of Stock [Line Items]
Preference shares conversion ratio	1.6929
Shares issued upon conversion of stock	23,200,000						0	0	23,345,000
Volume weighted average price per share | $ / shares			$ 29.54
Stock repurchase program, authorized repurchase amount | $											$ 2,500
Stock repurchase program, shares repurchased							11,410,000	0	67,817,000
Stock repurchase program, value repurchased | $							$ 0		$ 2,000
Stock repurchase program, remaining authorized repurchase amount | $				$ 135			$ 135	$ 500
Common shares, outstanding				746,390,932			746,390,932	755,222,727	748,528,000	510,483,000
Reclassification of certain tax effects, due to tax law changes | $							$ (253)
Reclassification of accumulated unrealized gains on available-for-sale securities | $					$ (9)		$ (9)
Unsettled share repurchases
Class of Stock [Line Items]
Stock repurchase program, shares repurchased							0	0
Preferred shares
Class of Stock [Line Items]
Preferred shares, outstanding				0			0	0
Preferred shares, authorized				7,000,000			7,000,000
Preferred shares, par value | $ / shares				$ 1			$ 1
6.375 percent Mandatory Convertible Preference Shares, Series A
Class of Stock [Line Items]
Preferred shares, outstanding	13,700,000
Preferred shares, par value | $ / shares		$ 1.00
New issuance		13,800,000
Preference shares, liquidation | $ / shares		$ 50.00
Net proceeds from issuance of preference shares | $		$ 669
Preferred Stock, Dividend Rate, Percentage	0.00%	0.00%
Pension
Class of Stock [Line Items]
Defined Benefit Plan, Plan Assets, Payment for Settlement | $				$ 200		$ 450		$ 0	$ 0