Changes in Shareholders' Equity - Changes in Minority Equity (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Comprehensive income (loss):
Amortization of prior service cost and unrecognized gains and losses included in total benefit cost, net of tax of $0 in 2015	$ 16	$ 19
Deferred derivative gains (losses), net of tax of $0 in 2015	(6)	13
Total comprehensive income (loss)	12	(50)
Changes in Minority Equity Presented Outside of Shareholders' Equity (Textuals)
Tax on foreign currency translation	17	(34)
Tax on amortization of prior service cost and unrecognized gains and losses included in total benefit cost	8	9
Tax on deferred derivative gains (losses)	$ (1)	2
Minority Shareholders' Equity - Redeemable
Changes in Minority Equity presented outside of Shareholders' Equity
Balance at beginning of period		582
Comprehensive income (loss):
Net income		9
Foreign currency translation, net of tax of $0 in 2015		(55)
Amortization of prior service cost and unrecognized gains and losses included in total benefit cost, net of tax of $0 in 2015		1
Deferred derivative gains (losses), net of tax of $0 in 2015		2
Other comprehensive income (loss)		(52)
Total comprehensive income (loss)		(43)
Balance at end of period		539
Changes in Minority Equity Presented Outside of Shareholders' Equity (Textuals)
Tax on foreign currency translation		0
Tax on amortization of prior service cost and unrecognized gains and losses included in total benefit cost		0
Tax on deferred derivative gains (losses)		$ 0