Retirement and Benefit Plans (Plan Assets Measured at Fair Value on a Recurring Basis) (Detail) - USD ($) $ in Millions		Dec. 31, 2018		Dec. 31, 2017
Defined Benefit Plan Disclosure
Plan assets		$ 164		$ 185
Cash equivalents
Defined Benefit Plan Disclosure
Plan assets		25		7
Mutual and exchange-traded funds
Defined Benefit Plan Disclosure
Plan assets	[1]	46		92
Debt securities
Defined Benefit Plan Disclosure
Plan assets	[1]	65		30
Debt securities | U.S. Treasury and federal agencies securities
Defined Benefit Plan Disclosure
Plan assets	[1]	46		12
Debt securities | Non-agency mortgage-backed securities
Defined Benefit Plan Disclosure
Plan assets	[1]	1		1
Debt securities | Asset-backed securities and other debt securities
Defined Benefit Plan Disclosure
Plan assets	[1],[2]	18		17
Collective funds
Defined Benefit Plan Disclosure
Plan assets	[3]	28		29
Excluding collective funds
Defined Benefit Plan Disclosure
Plan assets		136		156
Fair value level 1 | Cash equivalents
Defined Benefit Plan Disclosure
Plan assets		25		7
Fair value level 1 | Mutual and exchange-traded funds
Defined Benefit Plan Disclosure
Plan assets	[1]	46	[4]	92	[5]
Fair value level 1 | Debt securities
Defined Benefit Plan Disclosure
Plan assets	[1]	43	[4]	9	[5]
Fair value level 1 | Debt securities | U.S. Treasury and federal agencies securities
Defined Benefit Plan Disclosure
Plan assets	[1]	43	[4]	9	[5]
Fair value level 1 | Debt securities | Non-agency mortgage-backed securities
Defined Benefit Plan Disclosure
Plan assets	[1]	0	[4]	0	[5]
Fair value level 1 | Debt securities | Asset-backed securities and other debt securities
Defined Benefit Plan Disclosure
Plan assets	[1],[2]	0	[4]	0	[5]
Fair value level 1 | Excluding collective funds
Defined Benefit Plan Disclosure
Plan assets		114		135
Fair value level 2 | Cash equivalents
Defined Benefit Plan Disclosure
Plan assets		0		0
Fair value level 2 | Mutual and exchange-traded funds
Defined Benefit Plan Disclosure
Plan assets	[1]	0	[4]	0	[5]
Fair value level 2 | Debt securities
Defined Benefit Plan Disclosure
Plan assets	[1]	22	[4]	21	[5]
Fair value level 2 | Debt securities | U.S. Treasury and federal agencies securities
Defined Benefit Plan Disclosure
Plan assets	[1]	3	[4]	3	[5]
Fair value level 2 | Debt securities | Non-agency mortgage-backed securities
Defined Benefit Plan Disclosure
Plan assets	[1]	1	[4]	1	[5]
Fair value level 2 | Debt securities | Asset-backed securities and other debt securities
Defined Benefit Plan Disclosure
Plan assets	[1],[2]	18	[4]	17	[5]
Fair value level 2 | Excluding collective funds
Defined Benefit Plan Disclosure
Plan assets		22		21
Fair value level 3 | Cash equivalents
Defined Benefit Plan Disclosure
Plan assets		0		0
Fair value level 3 | Mutual and exchange-traded funds
Defined Benefit Plan Disclosure
Plan assets	[1]	0		0
Fair value level 3 | Debt securities
Defined Benefit Plan Disclosure
Plan assets	[1]	0		0
Fair value level 3 | Debt securities | U.S. Treasury and federal agencies securities
Defined Benefit Plan Disclosure
Plan assets	[1]	0		0
Fair value level 3 | Debt securities | Non-agency mortgage-backed securities
Defined Benefit Plan Disclosure
Plan assets	[1]	0		0
Fair value level 3 | Debt securities | Asset-backed securities and other debt securities
Defined Benefit Plan Disclosure
Plan assets	[1],[2]	0		0
Fair value level 3 | Excluding collective funds
Defined Benefit Plan Disclosure
Plan assets		$ 0		$ 0

[1] For further information on fair value hierarchy levels, refer to Note 1 .

[2] Includes corporate bond s.

[3] Certain investments that are measured at fair value using the NAV per share (or its equivalent) practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the fair value of Plan assets presented elsewhere within this footnote.

[4] During the year ended December 31, 2018 , no assets or liabilities were transferred between Level 1 and Level 2 .

[5] During the year ended December 31, 2017 , no assets or liabilities were transferred between Level 1 and Level 2 .