CONSOLIDATED STATEMENTS OF EQUITY (UNAUDITED) - USD ($) $ in Millions	Total	Parent	Common Stock	Additional Paid-in Capital	Retained Earnings	AOCI Attributable to Parent	Noncontrolling Interest
Accumulated other comprehensive income, beginning of year after accounting change					$ 4,876	$ (618)
Dividends					381
Other comprehensive income (loss)	$ 847					876
Net Income (Loss) Attributable to Parent	2,713
End of year at Dec. 31, 2014	16,387	$ 13,425
Accumulated other comprehensive income, beginning of year after accounting change					7,208	258
Dividends					912
Other comprehensive income (loss)	(860)					(845)
Net Income (Loss) Attributable to Parent	667
End of year at Dec. 31, 2015	15,530	12,471		$ 5,321	8,896	208	$ (3,059)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets				(1,933)		23
Accumulated other comprehensive income, beginning of year after accounting change					6,963	185
Other comprehensive income (loss)	726					723
Net Income (Loss) Attributable to Parent	950
End of year at Mar. 31, 2016	17,183	14,140			7,913	908
Beginning of year at Dec. 31, 2015	15,530	12,471		5,321	8,896	208	(3,059)
Other comprehensive income (loss)	1,331					1,331
Net Income (Loss) Attributable to Parent	1,434
End of year at Jun. 30, 2016	17,744	14,733			7,897	1,516
Beginning of year at Dec. 31, 2015	15,530	12,471		5,321	8,896	208	(3,059)
Net income (loss) attributable to noncontrolling interest							326
Dividends					(500)		(287)
Dividends paid to noncontrolling interest							92
Other comprehensive income (loss)	1,345					1,344	1
Net Income (Loss) Attributable to Parent	1,445				1,445
Other changes in noncontrolling interest				(8)			(5)
End of year at Sep. 30, 2016	17,764	14,752		5,313	7,908	1,529	3,012
Beginning of year at Dec. 31, 2015	15,530	12,471		5,321	8,896	208	(3,059)
Dividends					1,050
Other comprehensive income (loss)	(201)					(184)
Net Income (Loss) Attributable to Parent	28
End of year at Dec. 31, 2016	14,379	11,283		5,339	5,941	1	(3,096)
Beginning of year at Mar. 31, 2016	17,183	14,140			7,913	908
Other comprehensive income (loss)	605
Net Income (Loss) Attributable to Parent	485
End of year at Jun. 30, 2016	17,744	14,733			7,897	1,516
Other comprehensive income (loss)	15
Net Income (Loss) Attributable to Parent	11
End of year at Sep. 30, 2016	17,764	14,752		5,313	7,908	1,529	3,012
Common stock, at par value, beginning of year and end of period	2
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets				0		0
Accumulated other comprehensive income, beginning of year after accounting change					5,941	1
Beginning of year at Dec. 31, 2016	14,379	11,283		5,339	5,941	1	(3,096)
Other comprehensive income (loss)	143					136
Net Income (Loss) Attributable to Parent	(238)
End of year at Mar. 31, 2017	14,227	11,181			5,700	137
Beginning of year at Dec. 31, 2016	14,379	11,283		5,339	5,941	1	(3,096)
Other comprehensive income (loss)	438					451
Net Income (Loss) Attributable to Parent	1,362
End of year at Jun. 30, 2017	11,100	13,116			7,301	452
Beginning of year at Dec. 31, 2016	14,379	11,283		5,339	5,941	1	(3,096)
Net income (loss) attributable to noncontrolling interest							311
Dividends					0		(347)
Dividends paid to noncontrolling interest							96
Other comprehensive income (loss)	380					361	19
Net Income (Loss) Attributable to Parent					1,324
Other changes in noncontrolling interest				22			14
End of year at Sep. 30, 2017	15,959	12,990		5,361	7,265	362	2,969
Beginning of year at Mar. 31, 2017	14,227	11,181			5,700	137
Other comprehensive income (loss)	295
Net Income (Loss) Attributable to Parent	1,601
End of year at Jun. 30, 2017	11,100	13,116			7,301	452
Other comprehensive income (loss)	(52)
Net Income (Loss) Attributable to Parent	(56)
End of year at Sep. 30, 2017	15,959	$ 12,990		$ 5,361	$ 7,265	$ 362	$ 2,969
Common stock, at par value, beginning of year and end of period	$ 2		$ 2