SHAREHOLDERS' INTEREST - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions			1 Months Ended	12 Months Ended
	Jul. 08, 2013	Jun. 24, 2013	Apr. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Nov. 08, 2015	Aug. 27, 2015	Aug. 13, 2014
Class of Stock [Line Items]
New shares issued				0	0	33,350,000
Stock repurchase program, shares repurchased				16,190,000	6,063,000	0
Stock repurchase program, repurchase of common stock, cash settlement				$ 518	$ 203	$ 0
Stock repurchase program 2014
Class of Stock [Line Items]
Stock repurchase program, authorized repurchase amount									$ 700
Stock repurchase program, shares repurchased				15,471,962	6,062,993
Stock repurchase program, shares repurchased value				$ 497	$ 203
Stock repurchase program August 2015
Class of Stock [Line Items]
Stock repurchase program, authorized repurchase amount								$ 500
Stock repurchase program, shares repurchased				717,464
Stock repurchase program, shares repurchased value				$ 22
Stock repurchase program, remaining authorized repurchase amount				$ 478
Stock repurchase program November 2015
Class of Stock [Line Items]
Stock repurchase program, authorized repurchase amount							$ 2,500
Stock repurchase program, shares repurchased				0
Preferred shares
Class of Stock [Line Items]
Preferred shares, outstanding				0	0
Preferred shares, authorized				7,000,000
Preferred shares, par value				$ 1
6.375 percent Mandatory Convertible Preference Shares, Series A
Class of Stock [Line Items]
Preferred shares, outstanding				13,799,711	13,800,000
Preferred shares, authorized				40,000,000	40,000,000
Preferred shares, par value		$ 1.00		$ 1.00	$ 1.00
New shares issued		13,800,000
Preference shares, liquidation preference		$ 50.00		$ 50.00	$ 50.00
Net proceeds from issuance of preference shares		$ 669
Preference shares, dividend rate		6.375%
Conversion of Stock, Shares Converted			289
Common shares:
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities			436
New shares issued	4,400,000	29,000,000
Minimum | 6.375 percent Mandatory Convertible Preference Shares, Series A
Class of Stock [Line Items]
Preference shares, shares that will be issued upon conversion				1.5283
Maximum | 6.375 percent Mandatory Convertible Preference Shares, Series A
Class of Stock [Line Items]
Preference shares, shares that will be issued upon conversion				1.8339