Stockholders' Equity Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		$ 74,932
Ending Balance		74,966
Predecessor [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)			$ 122
Net other comprehensive income (loss)			488
Predecessor [Member] | Cumulative Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(2,843)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	[1]		378
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)			0
Net other comprehensive income (loss)			378
Ending Balance			(2,465)
Predecessor [Member] | Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			7
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			2
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)			(5)
Net other comprehensive income (loss)			(3)
Ending Balance			4
Predecessor [Member] | Unrealized gain (loss) on investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			2
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			1
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)			(1)
Net other comprehensive income (loss)			0
Ending Balance			2
Predecessor [Member] | Total
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(9,911)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			366
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)			122
Net other comprehensive income (loss)			488
Ending Balance			(9,423)
Successor [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)		(1)
Net other comprehensive income (loss)		972
Successor [Member] | Cumulative Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(454)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	[1]	957
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)		0
Net other comprehensive income (loss)		957
Ending Balance		503
Successor [Member] | Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(2)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		12
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)		(1)
Net other comprehensive income (loss)		11
Ending Balance		9
Successor [Member] | Unrealized gain (loss) on investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		0
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)		0
Net other comprehensive income (loss)		0
Ending Balance		0
Successor [Member] | Total
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(381)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		973
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)		(1)
Net other comprehensive income (loss)		972
Ending Balance		591
Other Benefit Plans | Predecessor [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(357)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			0
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)			4
Net other comprehensive income (loss)			4
Ending Balance			(353)
Other Benefit Plans | Successor [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		(53)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		0
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)		0
Net other comprehensive income (loss)		0
Ending Balance		(53)
Pension Plan | Predecessor [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(6,720)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			(15)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)			124
Net other comprehensive income (loss)			109
Ending Balance			$ (6,611)
Pension Plan | Successor [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance		128
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		4
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)		0
Net other comprehensive income (loss)		4
Ending Balance		$ 132

[1] The cumulative translation adjustment gain for the three months ended March 31, 2017 is primarily driven by the weakening of the U.S. dollar ("USD") against the European Euro ("EUR") and the Brazilian real ("BRL"). The currency translation gain for the three months ended March 31, 2018 was primarily driven by the weakening of the USD against the EUR, as well as the Danish Kroner.