Shareowners' Equity and Noncontrolling Interest (Summary of Changes in AOCI) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (7,964)	$ (7,484)	$ (7,964)	$ (7,484)	$ (8,333)	$ (8,334)	$ (7,344)	$ (7,619)
Other comprehensive (loss) income before reclassifications, net - Foreign Currency Translation	249	(276)	395	(237)
Amounts reclassified, pretax - Foreign Currency Translation	0	0	0	(1)
Tax reclassified - Foreign Currency Translation	0	0	0	0
Other comprehensive (loss) income before reclassifications, net - Pension	2	8	2	25
Amounts reclassified, pretax - Pension	132	128	263	254
Tax reclassified - Pension	50	47	98	93
Other comprehensive (loss) income before reclassifications, net - AFS Securities	20	19	(1)	57
Amounts reclassified, pretax - AFS Securities	24	25	407	52
Tax reclassified - AFS Securities	8	7	155	19
Other comprehensive (loss) income before reclassifications, net - Unrealized Hedging (Losses) Gains	50	26	100	143
Amounts reclassified, pretax - Unrealized Hedging (Losses) Gains	(5)	(45)	(10)	(107)
Tax reclassified - Unrealized Hedging (Losses) Gains	(1)	(11)	(2)	(28)
Other comprehensive (loss) income before reclassifications, net	299	(237)	449	(73)
Amounts reclassified, pretax	(113)	(148)	134	(310)
Tax reclassified	(43)	(51)	55	(102)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(3,128)	(2,685)	(3,128)	(2,685)	(3,359)	(3,480)	(2,411)	(2,438)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(4,882)	(4,999)	(4,882)	(4,999)	(4,962)	(5,045)	(5,072)	(5,135)
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	100	317	100	317	96	353	316	293
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(54)	(117)	(54)	(117)	$ (108)	$ (162)	$ (177)	$ (339)
Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive (loss) income before reclassifications, net - Foreign Currency Translation	$ 231	$ (274)	352	$ (248)
Investments in Watsco, Inc.
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified, pretax - Unrealized Hedging (Losses) Gains			$ 380